Stops komponent components from being listed in the style guide sidebar

[GeoffTidey]

• Updated README to include help on gem installation for appraisal tests
• Created komponent fixture components for path tests
• Added filter to remove any path that starts with ‘komponent/ from Komponent::Component.all

closes https://github.com/komposable/komponent/issues/164

[Spone]

Hi @GeoffTidey I don't see any change to the tests in your PR diff.

Can you confirm that you just needed to add the komponent/* components to the fixture app in order to test that they were not counted here?

[GeoffTidey]

Hey @Spone, it's been a while since I made this PR, but I have a recollection adding the komponent components to the fixtures was required.