Ongoing work on Metadata and Extensions Tutorials (#1011)

* Adding metadata tutorial page
* Fixing links to match new link contract
* updated rlink reference
* 857 extension mechanisms (#1031)
* Added json and yaml example snippets
* Added link to allowed values documentation
* Added hugo callouts and minor tweaks
* 857 updates (#1273)
* Completed an editorial pass through the metadata and extension tutorial. Revised the prop portion of the extension tutorial to provide a better conceptualization
* Reorganized the tutorials to follow the model layer organization.

Co-authored-by: David Waltermire <david.waltermire@nist.gov>
Co-authored-by: Alexander Stein <alexander.stein@nist.gov>
Co-authored-by: stephenbanghart <banghasa@dukes.jmu.edu>
Co-authored-by: Stephen Banghart <stephen.banghart@nist.gov>
Co-authored-by: Rene Tshiteya <rene-claude.tshiteya@noblis.org>
Co-authored-by: Rene2mt <76444659+Rene2mt@users.noreply.github.com>

build/config/.lycheeignore

@@ -1,4 +1,6 @@
 https://defense.gov/
+https://federal-agency.gov/.*
+http://federal-agency.gov/ns/oscal
 http://fedramp.gov/ns/oscal
 https://fedramp.gov/ns/oscal
 http://www.first.org/cvss/v2.0
@@ -10,3 +12,4 @@ http://csrc.nist.gov/oscal
 https://csrc.nist.gov/projects/cryptographic-module-validation-program/certificate/xxxx
 https://cdn.telos.com/wp-content/uploads/2021/06/22150746/Xacta-360-EULA-US.pdf
 https://search.usa.gov/search
+https://example.com/.*

docs/assets/scss/hugo-uswds-custom.scss

@@ -21,3 +21,8 @@
     float: inherit;
   }
 }
+
+div.highlight .chroma .err {
+  color: gray;
+  background-color: inherit;
+}

docs/content/concepts/layer/validation/_index.md → docs/content/concepts/validation/_index.md

@@ -4,6 +4,8 @@ weight: 50
 description: Explanation of well-formedness, validation, and how they relate to OSCAL
 aliases: []
 suppresstopiclist: true
+aliases:
+- /concepts/layer/validation/
 ---
 
 ## Who is this document for?

docs/content/learn/tutorials/_index.md

@@ -3,8 +3,18 @@ title: Walkthrough Tutorials
 suppresstopiclist: true
 ---
 
-The following tutorials provide a step-by-step walkthrough on explaining how to create OSCAL content of various types.
+The following tutorials provide step-by-step walk-throughs explaining how to create OSCAL content of various types.
 
-- [Creating a Basic Control Catalog](/learn/tutorials/catalog/): A tutorial on creating a [catalog](/concepts/terminology/#catalog) of [controls](/concepts/terminology/#control) using the OSCAL [catalog model](/concepts/layer/control/catalog/).
-- [Creating a Basic Component Definition](/learn/tutorials/component-definition/): A tutorial on creating a component-definition using the OSCAL [component definition model](/concepts/layer/implementation/component-definition/).
-- [Representing Test Validation Information](/learn/tutorials/validation-modeling/): A mini-tutorial on providing test validation information (e.g., FIPS 140-2 validation) as an OSCAL component in a [component definition](/concepts/layer/implementation/component-definition/) or [system security plan](/concepts/layer/implementation/ssp/).
+## [General Topics](general/)
+
+- [Using the metadata section](general/metadata/): Explains use of the `metadata` section that is required to be provided in all OSCAL content.
+- [Extending OSCAL models](general/extension/): Discusses how to use OSCAL properties and links to provided extended data in OSCAL content.
+
+## [Control Layer Topics](control/)
+
+- [Creating a Basic Control Catalog](control/basic-catalog/): Explains how to create a [catalog](/concepts/terminology/#catalog) of [controls](/concepts/terminology/#control) using the OSCAL [catalog model](/concepts/layer/control/catalog/).
+
+## [Implementation Layer Topics](implementation/)
+
+- [Creating a Basic Component Definition](implementation/basic-component-definition/): Teaches how to create a component-definition using the OSCAL [component definition](/concepts/layer/implementation/component-definition/) model.
+- [Representing test validation information](implementation/validation-modeling/): Describes how to represent test validation information (e.g., FIPS-140-2) using a component in an OSCAL [component definition](/concepts/layer/implementation/component-definition/) or [system security plan](/concepts/layer/implementation/ssp/). 

docs/content/learn/tutorials/control/_index.md

@@ -0,0 +1,13 @@
+---
+title: Control Layer Topics
+heading: Tutorials that apply to the OSCAL control layer models
+description: A set of tutorials that apply to the OSCAL [control layer](/concepts/layer/control/) models.
+weight: 20
+suppresstopiclist: true
+toc:
+  enabled: false
+---
+
+The following tutorial covers topics that apply to the OSCAL [control layer](/concepts/layer/control/) models.
+
+- [Creating a Basic Control Catalog](basic-catalog/): A tutorial on creating a [catalog](/concepts/terminology/#catalog) of [controls](/concepts/terminology/#control) using the OSCAL [catalog model](/concepts/layer/control/catalog/).

docs/content/learn/tutorials/catalog/_index.md → docs/content/learn/tutorials/control/basic-catalog.md

@@ -1,15 +1,18 @@
 ---
 title: Creating a Control Catalog
 description: A tutorial on creating an OSCAL control catalog.
-weight: 5
+weight: 20
 suppresstopiclist: true
 toc:
   enabled: true
 aliases:
   - /tutorials/catalog/
+  - /learn/tutorials/catalog/
 ---
 
-This tutorial covers creating a basic OSCAL control catalog. Before reading this tutorial you should:
+This tutorial covers creating a basic OSCAL control catalog.
+
+Before reading this tutorial you should:
 
 - Have some familiarity with the [XML](https://www.w3.org/standards/xml/core), [JSON](https://www.json.org/), or [YAML](https://yaml.org/spec/) formats.
 - Read the OSCAL control layer [overview](/concepts/layer/control/).

docs/content/learn/tutorials/general/_index.md

@@ -0,0 +1,14 @@
+---
+title: General Topics
+heading: Tutorials that apply to OSCAL as a whole
+description: A set of tutorials that apply to all OSCAL models.
+weight: 10
+suppresstopiclist: true
+toc:
+  enabled: false
+---
+
+The following tutorials cover general topics that apply to all of the OSCAL [models](/concepts/layer/).
+
+- [Using the metadata section](metadata/): Explains use of the `metadata` section that is required to be provided in all OSCAL content.
+- [Extending OSCAL models](extension/): A discussion of how to use OSCAL properties and links to provided extended data in OSCAL content.