add: pycln as a python linter and fixer (#4415)

this commit adds pycln as a Python linter and fixer, together with some
tests and documentation. It addresses #4340

pycln repo: https://github.com/hadialqattan/pycln

doc/ale-supported-languages-and-tools.txt

@@ -481,6 +481,7 @@ Notes:
   * `isort`
   * `mypy`
   * `prospector`!!
+  * `pycln`
   * `pycodestyle`
   * `pydocstyle`
   * `pyflakes`