feat: allow adding cookies from the UI directly and fix the ytdl bug

[zdimension]

Description

Cookies exported from a browser plugin can now be imported directly from the preferences page.

Cookies are now passed to Youtube-DL in a temporary file so writes by Youtube-DL are not saved (this was previously a problem).

Screenshot

(chrome plugin)

(prefs page)

Issues Fixed or Closed

Type of Change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Dependency update (updates to dependencies)
• Documentation update (changes to documentation)
• Repository update (changes to repository files, e.g. .github/...)

Checklist

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have added or updated the in code docstring/documentation-blocks for new or existing methods/components

Branch Updates

LizardByte requires that branches be up-to-date before merging. This means that after any PR is merged, this branch
must be updated before it can be merged. You must also
Allow edits from maintainers.

• I want maintainers to keep my branch updated

[codecov]

Codecov Report

Merging #215 (60fd8c1) into nightly (aba0560) will decrease coverage by 0.55%.
The diff coverage is 73.33%.

Additional details and impacted files

@@             Coverage Diff             @@
##           nightly     #215      +/-   ##
===========================================
- Coverage    67.85%   67.30%   -0.55%     
===========================================
  Files           11       11              
  Lines          815      838      +23     
===========================================
+ Hits           553      564      +11     
- Misses         262      274      +12     

Flag	Coverage Δ
Linux	67.30% <73.33%> (-0.55%)	⬇️
Windows	?

Flags with carried forward coverage won't be shown. Click here to find out more.

Files	Coverage Δ
Contents/Code/constants.py	85.71% <ø> (-0.40%)	⬇️
Contents/Code/default_prefs.py	100.00% <ø> (ø)
Contents/Code/youtube_dl_helper.py	74.32% <73.33%> (-11.68%)	⬇️