[FEATURE] Add throttle_protection plugin

[jmbannon]

Provides options to make ytdl-sub look more 'human-like' to protect from throttling. For range-based values, a random number will be chosen within the range to avoid sleeps looking scripted.

Usage:

    throttle_protection:
      sleep_per_download_s:
        min: 2.2
        max: 10.8
      sleep_per_subscription_s:
        min: 9.0
        max: 14.1
      max_downloads_per_subscription:
        min: 10
        max: 36
      subscription_download_probability: 1.0

[codecov]

Codecov Report

Merging #799 (e5c0cd0) into master (19eee28) will decrease coverage by 0.02%.
The diff coverage is 96.39%.

@@            Coverage Diff             @@
##           master     #799      +/-   ##
==========================================
- Coverage   96.84%   96.82%   -0.02%     
==========================================
  Files          78       79       +1     
  Lines        5003     5108     +105     
==========================================
+ Hits         4845     4946     +101     
- Misses        158      162       +4     

Files	Coverage Δ
src/ytdl_sub/cli/parsers/dl.py	100.00% <100.00%> (ø)
src/ytdl_sub/config/plugin_mapping.py	96.66% <100.00%> (ø)
src/ytdl_sub/config/preset.py	97.41% <100.00%> (ø)
src/ytdl_sub/validators/validators.py	99.18% <83.33%> (-0.82%)	⬇️
src/ytdl_sub/plugins/throttle_protection.py	96.73% <96.73%> (ø)