## Description
This re-lands #132353 with some additional options for keeping around the staging directory, so that the recipe for publishing docs can give those options and have the staging directory left around for deploying to the website.
Reverted in #132613
## Related Issues
- https://flutter-review.googlesource.com/c/recipes/+/49580
## Description
This cleans up a lot of issues with the API doc generation.
Here are the main changes:
- Rename `dartdoc.dart` to `create_api_docs.dart`
- Move the bulk of the operations out of `dev/bots/docs.sh` into `create_api_docs.dart`.
- Delete `dashing_postprocess.dart` and `java_and_objc.dart` and incorporate those operations into `create_api_docs.dart`.
- Refactor the doc generation into more understandable classes
- Bump the snippets tool version to 0.4.0 (the latest one)
- Centralize the information gathering about the Flutter repo into the new `FlutterInformation` class.
- Clean up the directory handling, and convert to using the `file` package for all file and directory paths.
- Add an `--output` option to docs.sh that specifies the location of the output ZIP file containing the docs.
- Defaults to placing the output in `dev/docs/api_docs.zip` (i.e. where the previous code generates the file).
- Moved all document generation into a temporary folder that is removed once the documents are generated, to avoid VSCode and other IDEs trying to index the thousands of HTML and JS files in the docs output.
- Updated pubspec dependencies.
## Tests
- Added tests for doc generation.
