YN-0926: Add file type filters for viewables in Loader

[ynbot]

Please describe the feature you have in mind and explain what the current shortcomings are?

Add filter by extension in Loader so it is easy to find files with specific extension like pdf, .mov, .mxf, .jpg, .jpeg, .png, etc.

Additional context:

_This issue was automatically created from AYON ticket YN-0926

[BigRoy]

Taking a look at this it's not super trivial, because I don't think we can via the get versions endpoint filter to only versions that have certain representations (not even e.g. must have representation name X or Y) but preferably even be able to find if it has any file with a certain extensions.

Might need some brainstorm with @martastain to discuss what would be a reasonable way to potentially add it.

The only other way would be to do an additional query in the loader UI, but that could easily start crawling through the version pagination because the additional filter will easily exhaust all the pages if you happen to filter to some exotic extension.

[BigRoy]

Pending issue: ynput/ayon-backend#1114
Being worked on here: ynput/ayon-backend#1115

[BigRoy]

Should be available now in core after the merge of #1879 which contained #2031 which contained #2052