Allow plugins to define their own URLs

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DO NOT REUSE CODE FROM coala unless you are the sole author or have requested permission from all authors of the given file to reuse it under MIT!

added process/pending_review label

tested manually, I can now have a http://127.0.0.1:8000/api/plugin/similar_ee endpoint :)

added size/XS label

added status/approved and removed process/pending_review labels

added process/pending_review label

removed process/pending_review label

added process/pending_review label

removed status/approved label

added status/approved and removed process/pending_review labels

approved this merge request

added process/pending_review label

removed process/pending_review label

approved this merge request

merged

removed status/approved label

added status/approved label