Add feature to flip the video horizontally

[jeffrey-cheung-tech]

Description

Adds feature to horizontally flip the video via the video filter in the settings menu

Related issues

Implements feature for #7178

Has this been tested?

• 👍 yes, I added tests to the test suite
• 💭 no, because this PR is a draft and still needs work
• 🙅 no, because this PR does not update server code
• 🙋 no, because I need help

[jeffrey-cheung-tech]

Note to self: Needs to be refactored and use the Video.js plugin system.

[Chocobozzz]

Thank you, but yes please create a plugin and a component so you can inject this in the settings menu :)

[jeffrey-cheung-tech]

The code is now a working MVP!

Bugs that I'm aware of:

• Not toggling selection checkmark for the mirror video button (Tried to implement, doesn't seem trivial)
• Internationalization or A11y (Only a concern, haven't tried to implement)

Any feedback is welcome!

[Chocobozzz]

Thank you!