[Enhancement] Improve privacy / make Invidious less detectable

[unixfox]

Is your enhancement request related to a problem? Please describe. YouTube is actively trying to restrict us. We should try to blend in with the crowd.

Describe the solution you'd like

• [ ] Randomize the user agent. Searx is already doing that: https://github.com/searx/searx/blob/master/searx/data/useragents.json
• [ ] Use a Firefox user agent. Google control chromium/chrome, so it can more easily detect some features that Invidious doesn't support compared to a real chromium/chrome browser.
• [x] Randomize CONSENT cookie ID
• [ ] Randomize some headers (which ones?)
• [ ] Use a newer version of QUIC: related iv-org/lsquic.cr#16
• [ ] Have a TLS fingerprint similar to Firefox or Chrome (hard to do in crystal) - https://fingerprint.com/blog/what-is-tls-fingerprinting-transport-layer-security/
• [ ] Use HTTP2 or HTTP3 - Modern browsers do not use HTTP1 anymore

Anything else?

[SamantazFox]

"Randomize CONSENT cookie ID" was done in #3893

[unixfox]

Added more things in the list to look like more of a browser.