Adding pre-commit

Introduced changes:
- pre-commit config and rules
- Add pre-commit to pep8 gate, Flake8 is covered in the pre-commit hooks.
- Applying fixes for pre-commit compliance in all code.

Also commit hash will be used instead of version tags in pre-commit to
prevend arbitrary code from running in developer's machines.

pre-commit will be used to:
- trailing whitespace;
- Replaces or checks mixed line ending (mixed-line-ending);
- Forbid files which have a UTF-8 byte-order marker (check-byte-order-marker);
- Checks that non-binary executables have a proper
  shebang (check-executables-have-shebangs);
- Check for files that contain merge conflict strings (check-merge-conflict);
- Check for debugger imports and py37+ breakpoint()
  calls in python source (debug-statements);
- Attempts to load all yaml files to verify syntax (check-yaml);
- Run flake8 checks (flake8) (local)

For further details about tests please refer to:
https://github.com/pre-commit/pre-commit-hooks



Change-Id: I04e73b8a70d32fec3e6131526e0bed0be8599c28
Signed-off-by: Moisés Guimarães de Medeiros <moguimar@redhat.com>