Add filtering by minimum-length and/or title substrings

[sophia-behling]

Some channels upload shorts as regular videos, which results in them not being filtered. There seem to be two basic cases:

1. The uploader marks the videos with #shorts or similar strings in the video title. This can be solved by adding a user-editable list of strings, which, if one of them appears in the video title, will cause that video to be hidden.
2. The very short regular videos have nothing in common other than being very short. This can be solved by adding a user-adjustable minimum length for videos, which will cause any shorter video to be hidden.

Example 1: A channel, which uploads some of its shorts as regular videos, but marks them with #shorts in the title. Implementing either filter would solve this problem.

Example 2: A channel, which uploads regular videos, some of which last for hours, whereas others last only a couple of seconds. Because they don't have a common title substring, only the minimum length filter would solve this problem.

Personally, I'd be perfectly happy with just the minimum length filter implemented; IMHO using either filter should be optional (on/off toggle).

Thank you :-)