Testing for providers requiring authorization

[k0mmsussert0d]

• [X] PR is based on the DEVELOP branch
• [X] Don't send big changes all at once. Split up big PRs into multiple smaller PRs that are easier to manage and review
• [X] Read the contribution guide

This PR demonstrates a proposed approach to testing torrent providers requiring authorization using animebytes as an example.

Authorization mechanism is a part of an individual provider implementation. Usually, it depends on credentials stored as attributes of a provider class. In this particular example of animebytes provider, username and passkey attributes store user-provided credentials.

When provider class is imported to the testing context, advanced configuration of the instance can performed by injecting custom attributes found in _meta.attr in the test YAML file.

To prevent credentials from getting leaked by VCR recording them in the request, VCR context configuration can be defined in _meta.vcr. In case of animebytes, credentials are supplied as username and torrent_pass query parameters, so they have to be stripped with filter_query_parameters=['username', 'torrent_pass'] param provided to use_cassette(). Reference

To sum up, this PR introduces:

• post-construction initialization step for provider instance
• customizing vcr configuration per-case
• some test cases for animebytes

[medariox]

Great job! Thank you for the exceptional effort 👍