Implement MediaWiki REST API render

[VadimKovalenkoSNF]

Fixes #1601
Depends on #1929

[kelson42]

@VadimKovalenkoSNF Is this end-point outpout different from WikimediaDesktop? How?

[VadimKovalenkoSNF]

@kelson42
WikimediaDesktop returns the full HTML of the page (in text/html format) and MediaWiki REST API the content inside div.mw-parser-output along with headhtml property the same (but should be retrieved from json first, similar to VisualEditor response). MediaWiki REST API render does not return content optimized for mobile representation as it was with mobile-sections. This is the MediaWiki Action API that returns parsed content and headhtml

Upd: MediaWiki REST API can return articles in Parsoid HTML format: example https://en.wikipedia.org/w/rest.php/v1/page/Canada/html

[codecov]

Codecov Report

Attention: 21 lines in your changes are missing coverage. Please review.

Comparison is base (8ebd7d0) 76.14% compared to head (d3c6f11) 75.88%.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1926      +/-   ##
==========================================
- Coverage   76.14%   75.88%   -0.27%     
==========================================
  Files          37       39       +2     
  Lines        2985     3035      +50     
  Branches      653      664      +11     
==========================================
+ Hits         2273     2303      +30     
- Misses        617      634      +17     
- Partials       95       98       +3     

Files	Coverage Δ
src/MediaWiki.ts	87.08% <100.00%> (+0.51%)	⬆️
src/mwoffliner.lib.ts	74.90% <100.00%> (+0.09%)	⬆️
src/renderers/abstract.renderer.ts	86.17% <ø> (ø)
src/renderers/mediawiki-rest-api.renderer.ts	100.00% <100.00%> (ø)
src/util/builders/url/api.director.ts	87.50% <100.00%> (-1.98%)	⬇️
src/util/builders/url/base.director.ts	84.21% <100.00%> (ø)
...c/util/builders/url/mediawiki-rest-api.director.ts	100.00% <100.00%> (ø)
src/util/const.ts	100.00% <100.00%> (ø)
src/Downloader.ts	70.17% <92.85%> (+1.00%)	⬆️
src/renderers/renderer.builder.ts	54.38% <40.00%> (-3.95%)	⬇️
... and 1 more

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[VadimKovalenkoSNF]

This PR should be closed. Current successor is PR #1947

[kelson42]

Superseeded by #1947