Adds `--client-certificate`, `--client-certificate-key`, `--client-certificate-password`

Authored-by: coletdjnz
Co-authored-by: df <fieldhouse@gmx.net>
Co-authored-by: pukkandan <pukkandan.ytdlp@gmail.com>

It should not removes fields that may be needed for `--load-infojson`.
Eg: `_ffmpeg_args`, `_has_drm`

Authored by: fstirlitz, pukkandan

* And fix some existing warnings

Authored by: fstirlitz

Authored by: fstirlitz, pukkandan

Using https://github.com/PyCQA/isort

    isort -m VERTICAL_HANGING_INDENT --py 36 -l 80 --rr -n --tc .

Using https://github.com/asottile/pyupgrade

1. `__future__` imports and `coding: utf-8` were removed
2. Files were rewritten with `pyupgrade --py36-plus --keep-percent-format`
3. f-strings were cherry-picked from `pyupgrade --py36-plus`

Extractors are left untouched (except removing header) to avoid unnecessary merge conflicts

Authored by fstirlitz, pukkandan

Notes:

* `_windows_write_string`: Fixed in 3.6
  * https://bugs.python.org/issue1602
  * PEP: https://www.python.org/dev/peps/pep-0528

* Windows UTF-8 fix: Fixed in 3.3
  * https://bugs.python.org/issue13216

* `__loader__`: is always present in 3.3+
  * https://bugs.python.org/issue14646

* `workaround_optparse_bug9161`: Fixed in 2.7
  * https://bugs.python.org/issue9161

Authored by: fstirlitz

Authored by fstirlitz, pukkandan

Related: https://github.com/TeamNewPipe/NewPipe/issues/8034
Authored-by: coletdjnz

Closes #2761

Closes #3074

Authored by: s0u1h

* Adds new functions `_initialize_pre_login` and `_perform_login` as part of the extractor API
* Adds `ie.supports_login` to the public API

* Move `_match_entry` and `post_extract` to `process_video_result`. It is also left in `process_info` for API compat
* `--list-...` options and `--force-write-archive` now obey filtering options
* Move `SponsorBlockPP` to `after_filter`. Closes https://github.com/yt-dlp/yt-dlp/issues/2536
* Reverts 4ec82a72 since this commit addresses the issue it was solving

Authored by: MinePlayersPE

[youtube] Support channel search
https://github.com/ytdl-org/youtube-dl/commit/78ce962f4fe020994c216dd2671546fbe58a5c67

Closes #2419

Closes #2334

Closes #2343
Authored by: pukkandan, trassshhub

Closes #2388

Closes #2269

Authored by: zmousm, pukkandan

and add functions to return the HTML of elements

Authored by: zmousm

Authored by: iw0nderhow, pukkandan

Authored by: nixxo