Add support for encrypted query parameters

[Fijxu]

May close #2142

Encrypts sensitive query parameters that should be hidden to users like ip and pot using the hmac_key config option.

Taken from iv-org/invidious-companion#65

There is some problems with this current implementation:

• The hmac_key config option needs to be at least 16 characters, if we force it, that will break some setups on a new update. I have thought of 3 ways to fix this:
  • add characters to the hmac_key for the ecb_without_salt function until it has 16 (which is the minimum required for AES) if it's less than 16
  • use invidious_companion_key
  • introduce a new config option like invidious_companion_key but to encrypt the video query parameters.
• IP address and PoToken are still leaked if the video is not proxied and quality is set to medium, but that can be solved by forcing Proxy videos player preferences (Like I did here: https://git.nadeko.net/Fijxu/invidious/commit/7c9f79e1f146c59370bbe5e7abe82d37ec5fd5de). This will depend of the instance maintainer operator since proxying every video will use a lot of bandwidth, specially on public instances
• Any other videoplayback proxy without support for the encrypted parameters will not work, like https://github.com/TeamPiped/piped-proxy and https://github.com/TeamPiped/http3-ytproxy (But my fork supports it: https://git.nadeko.net/Fijxu/http3-ytproxy/src/commit/a6a33526a494a0719139602ec99c437dd64d81ef/internal/paths/videoplayback.go#L77)

Since Invidious companion will be become the official way to fetch youtube videos and videoplayback proxying, this may not be very useful on the future since companion is already able to encrypt the ip and pot query parameters, but will work for old setups that are still using inv_sig_helper for whatever reason (low memory capacity for example, since Invidious companion uses way more memory than inv_sig_helper)

[Fijxu]

Oops, I didn't know that require "uri/params/serializable" was unsupported on Crystal <=1.13.3 (https://github.com/iv-org/invidious/actions/runs/16105127771/job/45439447127?pr=5381#step:7:11). I guess I'll do it another way then