add devcontainer+pre-commit (#11328)

* add devcontainer support

* chore(devcontainer): install test requirements

* chore: add pre-commit

* fix format of pre-commit config file

* add licenses for the new files

* Apply suggestions from code review

* move requirements-dev.txt to inside .devcontainer

* specify files for ruff

* update CONTRIBUTING.md

* chore(devcontainer): use standard image, no docker build

* docs: format CONTRIBUTING.md (automatic by IDE)

* Update .devcontainer/devcontainer.json

* remove extraneous edits in CONTRIBUTING.md

CONTRIBUTING.md

@@ -133,6 +133,7 @@ ansible-test sanity --docker -v plugins/modules/system/pids.py tests/integration
 Note that for running unit tests, you need to install required collections in the same folder structure that `community.general` is checked out in.
 Right now, you need to install [`community.internal_test_tools`](https://github.com/ansible-collections/community.internal_test_tools).
 If you want to use the latest version from GitHub, you can run:
+
 ```
 git clone https://github.com/ansible-collections/community.internal_test_tools.git ~/dev/ansible_collections/community/internal_test_tools
 ```
@@ -155,6 +156,7 @@ ansible-test units --docker -v --python 3.8 tests/unit/plugins/modules/net_tools
 Note that for running integration tests, you need to install required collections in the same folder structure that `community.general` is checked out in.
 Right now, depending on the test, you need to install [`ansible.posix`](https://github.com/ansible-collections/ansible.posix), [`community.crypto`](https://github.com/ansible-collections/community.crypto), and [`community.docker`](https://github.com/ansible-collections/community.docker):
 If you want to use the latest versions from GitHub, you can run:
+
 ```
 mkdir -p ~/dev/ansible_collections/ansible
 git clone https://github.com/ansible-collections/ansible.posix.git ~/dev/ansible_collections/ansible/posix
@@ -167,11 +169,13 @@ The following commands show how to run integration tests:
 #### In Docker
 
 Integration tests on Docker have the following parameters:
+
 - `image_name` (required): The name of the Docker image. To get the list of supported Docker images, run
   `ansible-test integration --help` and look for _target docker images_.
 - `test_name` (optional): The name of the integration test.
   For modules, this equals the short name of the module; for example, `pacman` in case of `community.general.pacman`.
   For plugins, the plugin type is added before the plugin's short name, for example `callback_yaml` for the `community.general.yaml` callback.
+
 ```.bash
 # Test all plugins/modules on fedora40
 ansible-test integration -v --docker fedora40
@@ -192,6 +196,31 @@ ansible-test integration -v lookup_flattened
 
 If you are unsure about the integration test target name for a module or plugin, you can take a look in `tests/integration/targets/`. Tests for plugins have the plugin type prepended.
 
+## Devcontainer
+
+Since community.general 12.2.0, the project repository supports [devcontainers](https://containers.dev/). In short, it is a standard mechanism to
+create a container that is then used during the development cycle. Many tools are pre-installed in the container and will be already available
+to you as a developer. A number of different IDEs support that configuration, the most prominent ones being VSCode and PyCharm.
+
+See the files under [.devcontainer](.devcontainer) for details on what is deployed inside that container.
+
+Beware of:
+
+- By default, the devcontainer installs the latest version of `ansible-core`.
+  When testing your changes locally, keep in mind that the collection must support older versions of
+  `ansible-core` and, depending on what is being tested, results may vary.
+- Integration tests executed directly inside the devcontainer without isolation (see above) may fail if
+  they expected to be run in full fledged VMs. On the other hand, the devcontainer setup allows running
+  containers inside the container (the `docker-in-docker` feature).
+- The devcontainer is built with a directory structure such that
+  `.../ansible_collections/community/general` contains the project repository, so `ansible-test` and
+  other standard tools should work without any additional setup
+- By default, the devcontainer installs `pre-commit` and configures it to perform `ruff check` and
+  `ruff format` on the Python files, prior to commiting. That configuration is going to be used by
+  `git` even outside the devcontainer. To prevent errors, you have to either install `pre-commit` in
+  your computer, outside the devcontainer, or run `pre-commit uninstall` from within the devcontainer
+  before quitting it.
+
 ## Creating new modules or plugins
 
 Creating new modules and plugins requires a bit more work than other Pull Requests.
@@ -201,7 +230,7 @@ Creating new modules and plugins requires a bit more work than other Pull Reques
 
 2. Please do not add more than one plugin/module in one PR, especially if it is the first plugin/module you are contributing.
    That makes it easier for reviewers, and increases the chance that your PR will get merged. If you plan to contribute a group
-   of plugins/modules (say, more than a module and a corresponding ``_info`` module), please mention that in the first PR. In
+   of plugins/modules (say, more than a module and a corresponding `_info` module), please mention that in the first PR. In
    such cases, you also have to think whether it is better to publish the group of plugins/modules in a new collection.
 
 3. When creating a new module or plugin, please make sure that you follow various guidelines: