feat: add filetype and mediatype searches

[python357-1]

fixes #574

added search types filetype: and mediatype:

example library:

filetype search example:

mediatype search example:

[python357-1]

i did try and add some tests based on what i was seeing from other tests, but i couldn't really tell how a library gets passed to tests so if they aren't correct, feel free to fix/point me to some information on how to fix them

[CyanVoxel]

Looks great, thank you for this! Approved when the comment is addressed (might be a good addition to the test cases, too)