Add tags to studios

[bob123491234]

Allows tags to be added to studios.

Everything functions as expected, but there are a number of errors relating to missing methods in the mock files. I don't know what I am missing in order to make it generate the methods.

Resolves #2497

[WithoutPants]

Run make generate-test-mocks

[WithoutPants]

Thanks for your contribution @bob123491234. I removed the studio_tags filter from the filter types since these are handled by the studios_filter field. The nested filters aren't yet integrated into the UI, so for the sake of expediency I've removed these from the UI for the time being.

You are eligible for the bounty on #2497. Please submit an expense request for $33.51 (which is the net amount after OpenCC fees), with Bounty issue #2497 ($40 minus fees) as the description. Add a comment here with the link so that I can verify the expense is yours.

Alternatively, if you prefer to reassign the bounty to another issue, let me know.