Asciidoctor conversion first step

* Shell script using pandoc to convert from .md to .adoc
* Initial OmniSpec.adoc
* build.gradle to render PDF & HTML via Github actions
* .github/workflows/gradle.yml

adoc spec: cleanup metadata, note, at TOC

OmniSpec.adoc: Minor syntax cleanup

Gradle build: move doc output to build/doc

Simplify to just Github Actions/gradle rendering

* Remove the converted README/spec (that’s in another PR now)
* Remove the conversion Bash script
* Change build.gradle to reflect the Spec will be in README.adoc

Add renderOmniSpecification Gradle task

.github/workflows/gradle.yml

@@ -0,0 +1,21 @@
+name: Documentation Build
+
+on: [push, pull_request]
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    name: Asciidoctor Gradle
+    steps:
+    - uses: actions/checkout@v1
+    - name: Set up JDK
+      uses: actions/setup-java@v1
+      with:
+        java-version: 11
+    - name: Build with Gradle
+      run: gradle renderOmniSpecification --info --stacktrace
+    - name: Upload build directory as artifact
+      uses: actions/upload-artifact@master
+      with:
+        name: omni-spec-documentation-archive
+        path: build/doc

.gitignore

@@ -0,0 +1,4 @@
+.gradle/
+build/
+.idea/
+

build.gradle

@@ -0,0 +1,32 @@
+buildscript {
+    repositories {
+        jcenter()
+    }
+}
+
+plugins {
+    id 'org.asciidoctor.jvm.convert' version '2.3.0'
+    id 'org.asciidoctor.jvm.pdf' version '2.3.0'
+}
+
+repositories {
+    jcenter()
+}
+
+asciidoctor {
+  sourceDir file("$projectDir")
+  sources {
+    include 'README.adoc'
+  }
+  outputDir  file('build/doc')
+}
+
+asciidoctorPdf {
+  sourceDir file("$projectDir")
+  sources {
+    include 'README.adoc'
+  }
+  outputDir  file('build/doc')
+}
+
+task renderOmniSpecification(dependsOn: [asciidoctor, asciidoctorPdf])