Add support for AI-powered summarization

[waybackarchiver]

Description

• Update changelog
• Update documentation
• Makes it more customisable (refine WAYBACK_COHERE_APIKEY)

Closes #329
Closes #135

Checklist

• I have followed the contributing guidelines
• I have reviewed and understood the Code of Conduct
• I have searched and make sure there's no duplicate PRs

[codecov]

Codecov Report

❌ Patch coverage is 54.73684% with 43 lines in your changes missing coverage. Please review.
✅ Project coverage is 47.93%. Comparing base (da72fdf) to head (6086dc5).
⚠️ Report is 50 commits behind head on main.

Files with missing lines	Patch %	Lines
template/render/render.go	28.00%	15 Missing and 3 partials ⚠️
summary/cohere.go	42.85%	11 Missing and 1 partial ⚠️
reduxer/reduxer.go	54.54%	4 Missing and 1 partial ⚠️
summary/locally.go	75.00%	3 Missing and 1 partial ⚠️
config/options.go	33.33%	2 Missing ⚠️
config/parser.go	0.00%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #394      +/-   ##
==========================================
+ Coverage   47.87%   47.93%   +0.06%     
==========================================
  Files          60       63       +3     
  Lines        5496     5582      +86     
==========================================
+ Hits         2631     2676      +45     
- Misses       2591     2626      +35     
- Partials      274      280       +6     

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[github-actions]

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[github-actions]

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[github-actions]

It has been open 120 days with no activity. Remove stale label or comment or this will be closed in 5 days

[github-actions]

It has been open 120 days with no activity. Remove stale label or comment or this will be closed in 5 days

[github-actions]

It has been open 120 days with no activity. Remove stale label or comment or this will be closed in 5 days