WIP [ENH, DOC] Documentation PDF - automatic generation

[juangpc]

Hi,
The pr will create a pdf from the markdown files in the doc/gh-pages folder. Eventually, it could turn into an independent repository with a gh action that we could download from the ci, and trigger whenever a pr was accepted into master.

Coded in Python, and based in a Latex template, it creates two python modules (so far). One a basic mne-cpp core module with basic functions we might need during development, and another module related to the actual pdf generation.

To do:

• - Analyze markdown files in doc/gh-pages folder.
• - Generate a graph of connections and dependencies between md files: a web page.
• - Generate a list of md files to not include in the pdf. (i.e. a Download page) This shouldn't rely in just the docs.
• - Create an initial Latex file.
• - Finish python parser (see below)
• - Validate and test all the parsing routines created.
• - Generate a single shell or python command that takes care of everything.
• - Generate a CI action that calls the script and saves the corresponding pdf as an asset that we can then link in the actual web. We should do that through a markdown link itself (this page should probably not be included in the pdf).

Python parser code:

• - correctly parse ordered / unordered combined lists.
• - parse inbound links vs outbound links
• - parse inline code
• - parse multiple terms description/definition

Yes, the pr needs still some work.

[codecov-commenter]

Codecov Report

Merging #797 (bcd13bd) into main (5f0f608) will not change coverage.
The diff coverage is n/a.

❗ Current head bcd13bd differs from pull request most recent head 4b3f914. Consider uploading reports for the commit 4b3f914 to get more accurate results

@@           Coverage Diff           @@
##             main     #797   +/-   ##
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  Coverage   29.52%   29.52%           
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  Files         450      450           
  Lines       39296    39296           
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  Hits        11603    11603           
  Misses      27693    27693           

Impacted Files	Coverage Δ
libraries/utils/generics/applicationlogger.cpp	62.50% <0.00%> (-2.21%)	⬇️
...aries/disp3D/helpers/geometryinfo/geometryinfo.cpp	96.62% <0.00%> (-1.13%)	⬇️
libraries/mne/c/mne_surface_or_volume.cpp	48.71% <0.00%> (+0.05%)	⬆️
...pplications/mne_anonymize/settingscontrollercl.cpp	70.00% <0.00%> (+0.12%)	⬆️