Deescovery

* Set default action for ModuleRule: import it.

* Updated documentation.

* (backward-incompatible) Renamed a matcher: `MatchByCallableAttribute` to `MatchByMethod`
* Added support for Python3.10
* Updated documentation for module and object rules.
* Updated documentation for matchers.
* Added an example for Typer.
* Reorganized API documentation.

* Added MatchBySubclass object matcher.
* Updated project documentation.
* Updated pre-commit hooks.

* Fixed an accidentally introduced incompatibility with python3.7 and 3.8.

* Flask rules: add support for flat domain package structure.