Apply and enforce file-level license headers (#63)

* Apply and enforce file-level license headers

Use `mattermost-govet` and `eslint`'s `header/header` to ensure each
file begins with the appropriate header, then fix all instances for
built source code. (e2e code excepted)

```
// Copyright (c) 2014-present Mattermost, Inc. All Rights Reserved.
// See LICENSE.txt for license information.
```

Note that this renames `LICENSE` to `LICENSE.txt` purely to align on the
copyright messaging across repos.

* bundle LICENSE.txt and NOTICE.txt if they exist

* updated NOTICE.txt and configuration

.config/notice-file/README.md

@@ -0,0 +1,28 @@
+# Notice.txt File Configuration
+
+We are automatically generating Notice.txt by using first-level dependencies of the project. The related pipeline uses `config.yaml` stored in this folder.
+
+
+## Configuration
+
+Sample:
+
+```
+title: "Mattermost Playbooks"
+copyright: "©2015-present Mattermost, Inc.  All Rights Reserved.  See LICENSE for license information."
+description: "This document includes a list of open source components used in Mattermost Playbooks, including those that have been modified."
+search:
+  - "go.mod"
+  - "client/go.mod"
+dependencies: []
+devDependencies: []
+```
+
+| Field | Type   | Purpose |
+| :--   | :--    | :--     |
+| title | string | Field content will be used as a title of the application. See first line of `NOTICE.txt` file. |
+| copyright | string | Field content will be used as a copyright message. See second line of `NOTICE.txt` file. |
+| description | string | Field content will be used as notice file description. See third line of `NOTICE.txt` file. |
+| dependencies | array | If any dependency name mentioned, it will be automatically added even if it is not a first-level dependency. |
+| devDependencies | array | If any dependency name mentioned, it will be added when it is referenced in devDependency section. |
+| search | array | Pipeline will search for package.json/go.mod files mentioned here. Globstar format is supported ie. `x/**/go.mod`. |

.config/notice-file/config.yaml

@@ -0,0 +1,9 @@
+---
+title: "Mattermost User Survey Plugin"
+copyright: "©2024-present Mattermost, Inc. All Rights Reserved. See LICENSE.txt for license information."
+description: "This document includes a list of open source components used in the plugin, including those that have been modified."
+search:
+  - "go.mod"
+  - "webapp/package.json"
+dependencies: []
+devDependencies: []

.gitignore

@@ -16,3 +16,6 @@ go.work
 go.work.sum
 
 webapp/.stylelintcache
+
+# notice
+.notice-work

Makefile

@@ -160,6 +160,7 @@ install-go-tools:
 	@echo Installing go tools
 	$(GO) install github.com/golangci/golangci-lint/cmd/golangci-lint@v1.57.2
 	$(GO) install gotest.tools/gotestsum@v1.11.0
+	$(GO) install github.com/mattermost/mattermost-govet/v2@3f08281c344327ac09364f196b15f9a81c7eff08
 
 ## Runs eslint and golangci-lint
 .PHONY: check-style
@@ -178,6 +179,7 @@ ifneq ($(HAS_SERVER),)
 	@echo Running golangci-lint
 	$(GO) vet ./...
 	$(GOBIN)/golangci-lint run ./...
+	$(GO) vet -vettool=$(GOBIN)/mattermost-govet -license -license.year=2024 ./...
 endif
 
 ## Runs eslint and golangci-lint auto style fixes
@@ -265,6 +267,12 @@ bundle:
 	rm -rf dist/
 	mkdir -p dist/$(PLUGIN_ID)
 	./build/bin/manifest dist
+ifneq ($(wildcard LICENSE.txt),)
+	cp -r LICENSE.txt dist/$(PLUGIN_ID)/
+endif
+ifneq ($(wildcard NOTICE.txt),)
+	cp -r NOTICE.txt dist/$(PLUGIN_ID)/
+endif
 ifneq ($(wildcard $(ASSETS_DIR)/.),)
 	cp -r $(ASSETS_DIR) dist/$(PLUGIN_ID)/
 endif