Flake8 CI fixes (#451)

* Pep8 fixes

* tox Pep8 compliance

* Excluded external tools folder from flake 8 tests

* Added Flake 8 exclusions

* Pep8 fixes

* Pep8 fixes

* Corrected type

* Pep8 fixes

* Pep 8 compliance

* Pep8 fixes

* Pep8  fixes

* Pep8 fixes

* Pep8 fixes

* Pep 8 fixes

* Pep 8 fixes

* Pep8 fixes

* Pep8 fixes

* Pep8 fixes

* Pep8

* Pep8

* Pep 8

* Pep 8

* Pep8 fixes

* Pep8

* Pep8

* Pep8

* Pep8 fixes

* Pep8 fixes

* Pep8 fixes

* Pep8 fixes

* Pep8 fixes

* Revert chagnes

* Revert changes to kivy/__init.py

* Revert changes

* REvert changes

* Revert changes

* Revert changes to toolchain

* Add files exclusions to tox.ini

* Added exclusions for alias recipes

* Remove dead code

* Added py extension to recipes

* Removed recipe build skip

* Improves recipe matching

Previous expression was matching all the following three lines of a `git diff --name-only` output.
```
recipes/hostlibffi/__init__.py
recipes/hostpython.py
recipes/hostpython2/__init__.py
```
This was resulting to a bug when later splitting with `recipe = file_path.split('/')[1]` the `recipes/hostpython.py` string would return including the `\n` new line char, see:
 ```
>>> 'recipes/hostpython.py\n'.split('/')[1]
'hostpython.py\n'
>>> 'recipes/hostlibffi/__init__.py\n'.split('/')[1]
'hostlibffi'
>>> 
```

Co-authored-by: Andre Miras <AndreMiras@users.noreply.github.com>

tests/test_python3/main.py

@@ -1,7 +1,6 @@
 print("Python 3 running!")
 import sys
 print(f"sys.path: {sys.path}")
-import os
 import traceback
 
 modules_to_tests = [
@@ -21,17 +20,18 @@ for name in modules_to_tests:
 
 # test pyobjus
 print("- import pyobjus start")
-import pyobjus
+import pyobjus  # noqa: F401
 print("- import done")
 from pyobjus import autoclass
 NSNotificationCenter = autoclass("NSNotificationCenter")
 
 # test ios
-import ios
+import ios  # noqa: F401
 
 from kivy.app import App
 from kivy.lang import Builder
 
+
 class TestApp(App):
     def build(self):
         return Builder.load_string("""
@@ -51,4 +51,5 @@ RelativeLayout:
 
 """)
 
+
 TestApp().run()