DEV: Modernize codebase (#2)

This theme-component was recently moved from my personal profile (`/keegangeorge/discourse-copy-post`) to the Discourse org profile. Along with that move, we want to make some modernizations to prepare this theme-component to become #official. This PR handles those modernizations. 

In particular we:
- update linting, configs, workflows, etc.
- remove widget in favour of Glimmer `.gjs` component
- update API usage to use `valueTransformer` instead of `decorateWidget` to add the post menu button
- make improvements to behaviour by way of introducing new settings:
   - choosing between Markdown / HTML for the copied post
   - using `allowed_groups` setting instead of trust level setting
- remove acceptance test in favour of system spec

.github/workflows/discourse-theme.yml

@@ -0,0 +1,11 @@
+name: Discourse Theme
+
+on:
+  push:
+    branches:
+      - main
+  pull_request:
+
+jobs:
+  ci:
+    uses: discourse/.github/.github/workflows/discourse-theme.yml@v1

.npmrc

@@ -0,0 +1,2 @@
+engine-strict = true
+auto-install-peers = false

.rubocop.yml

@@ -0,0 +1,2 @@
+inherit_gem:
+  rubocop-discourse: stree-compat.yml

.streerc

@@ -0,0 +1,2 @@
+--print-width=100
+--plugins=plugin/trailing_comma,plugin/disable_auto_ternary

.template-lintrc.js

@@ -1,4 +1 @@
-module.exports = {
-  plugins: ["ember-template-lint-plugin-discourse"],
-  extends: "discourse:recommended",
-};
+module.exports = require("@discourse/lint-configs/template-lint");

Gemfile

@@ -0,0 +1,8 @@
+# frozen_string_literal: true
+
+source "https://rubygems.org"
+
+group :development do
+  gem "rubocop-discourse"
+  gem "syntax_tree"
+end

Gemfile.lock

@@ -0,0 +1,91 @@
+GEM
+  remote: https://rubygems.org/
+  specs:
+    activesupport (7.2.2.1)
+      base64
+      benchmark (>= 0.3)
+      bigdecimal
+      concurrent-ruby (~> 1.0, >= 1.3.1)
+      connection_pool (>= 2.2.5)
+      drb
+      i18n (>= 1.6, < 2)
+      logger (>= 1.4.2)
+      minitest (>= 5.1)
+      securerandom (>= 0.3)
+      tzinfo (~> 2.0, >= 2.0.5)
+    ast (2.4.2)
+    base64 (0.2.0)
+    benchmark (0.4.0)
+    bigdecimal (3.1.9)
+    concurrent-ruby (1.3.4)
+    connection_pool (2.5.0)
+    drb (2.2.1)
+    i18n (1.14.6)
+      concurrent-ruby (~> 1.0)
+    json (2.9.1)
+    language_server-protocol (3.17.0.3)
+    logger (1.6.5)
+    minitest (5.25.4)
+    parallel (1.26.3)
+    parser (3.3.6.0)
+      ast (~> 2.4.1)
+      racc
+    prettier_print (1.2.1)
+    racc (1.8.1)
+    rack (3.1.8)
+    rainbow (3.1.1)
+    regexp_parser (2.10.0)
+    rubocop (1.69.2)
+      json (~> 2.3)
+      language_server-protocol (>= 3.17.0)
+      parallel (~> 1.10)
+      parser (>= 3.3.0.2)
+      rainbow (>= 2.2.2, < 4.0)
+      regexp_parser (>= 2.9.3, < 3.0)
+      rubocop-ast (>= 1.36.2, < 2.0)
+      ruby-progressbar (~> 1.7)
+      unicode-display_width (>= 2.4.0, < 4.0)
+    rubocop-ast (1.37.0)
+      parser (>= 3.3.1.0)
+    rubocop-capybara (2.21.0)
+      rubocop (~> 1.41)
+    rubocop-discourse (3.9.2)
+      activesupport (>= 6.1)
+      rubocop (>= 1.59.0)
+      rubocop-capybara (>= 2.0.0)
+      rubocop-factory_bot (>= 2.0.0)
+      rubocop-rails (>= 2.25.0)
+      rubocop-rspec (>= 3.0.1)
+      rubocop-rspec_rails (>= 2.30.0)
+    rubocop-factory_bot (2.26.1)
+      rubocop (~> 1.61)
+    rubocop-rails (2.28.0)
+      activesupport (>= 4.2.0)
+      rack (>= 1.1)
+      rubocop (>= 1.52.0, < 2.0)
+      rubocop-ast (>= 1.31.1, < 2.0)
+    rubocop-rspec (3.3.0)
+      rubocop (~> 1.61)
+    rubocop-rspec_rails (2.30.0)
+      rubocop (~> 1.61)
+      rubocop-rspec (~> 3, >= 3.0.1)
+    ruby-progressbar (1.13.0)
+    securerandom (0.4.1)
+    syntax_tree (6.2.0)
+      prettier_print (>= 1.2.0)
+    tzinfo (2.0.6)
+      concurrent-ruby (~> 1.0)
+    unicode-display_width (3.1.3)
+      unicode-emoji (~> 4.0, >= 4.0.4)
+    unicode-emoji (4.0.4)
+
+PLATFORMS
+  arm64-darwin-22
+  ruby
+
+DEPENDENCIES
+  rubocop-discourse
+  syntax_tree
+
+BUNDLED WITH
+   2.5.22

LICENSE

@@ -0,0 +1,21 @@
+The MIT License (MIT)
+
+Copyright (c) Civilized Discourse Construction Kit, Inc.
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.