Complete documentation

Previously, there were gaps in the API documentation for this project.
This change fills in those gaps and ensures that a full rake run will
pass.
Document Logging

Previously there was no documentation for the logging API exposed by
buildpack-support.  This change adds that documentation.

[#71230092]
Merge 71230092-document-logging to master

[Completes #71230092]
Test Fix

The previous commit made a code change that broke the tests.  This
change fixes those tests.
Document repository utilities

Previously the repository utilities were not documented sufficiently.
This change adds that documentation.

[#71230188]
Merge 71230188-document-repository to master

[Completes #71230188]
Test the directory_finder utility

The existing directory_finder implementation was not tested. This change adds
new examples for the directory_finder spec. with_load_path test utility added
to the global spce as a part of the new tests.

[#71229624]
Merge branch 'cgfrost-71229624-test-directory-finder'
Test the qualify_path utility

The existing qualify_path mixin implementation was not tested. This change
updates the previous pull request to not create a test stub class inside it's
own module as well as the original change to adds new examples for the
qualify_path spec.