VideoFrameSequence as a potential alternative to ImageSequence, Optional Cache Location, added repeat methods

[JingchengYang4]

• ImageSequence seems to perform oddly in some cases, its implementation is overcomplicating the actual expected features. It produces issues when the fps does not match and requires users to calculate durations etc. I've tried using it and it creates gaps between videos with missing frames etc.
• VideoFrameSequence is a simpler implementation that solves all the said problems, it's also made to work well with mv.repeat and its new features.
• Allow users to specify the location of disk-cache for compositions. It does seem like the library does not properly dispose disk-caches after processing, so I just made a quick fix allowing users to specify the location of the disk cache so they can dispose that folder when done rendering/
• Added a parameter to change the repeat method. The standard method of replaying the video is now the "loop" method, default parameter when calling mv.repeat. However, users can now also use "bounce" to repeat the video backwards after it has completed. (then forward -> backwards -> forward etc.)

[rezoo]

Thank you for your PR! This excellent PR resolves multiple issues, so it might take some time to review. However, I will thoroughly read it at the end of the workday. Just wanted to let you know for now.