Add copy buttons for documentation

[amageh]

Implements suggestions from issue #341. The package sphinx-copybutton adds buttons to all code blocks in the documentation, so I added code blocks for the algorithms and installation page.

[codecov]

Codecov Report

Merging #365 (5b6610f) into main (89a7e4e) will decrease coverage by 0.02%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##             main     #365      +/-   ##
==========================================
- Coverage   93.61%   93.58%   -0.03%     
==========================================
  Files         191      191              
  Lines       15357    15357              
==========================================
- Hits        14376    14372       -4     
- Misses        981      985       +4     

Impacted Files	Coverage Δ
...ptimization/subsolvers/bounded_newton_quadratic.py	85.08% <0.00%> (-0.88%)	⬇️
...magic/optimization/subsolvers/_trsbox_quadratic.py	84.08% <0.00%> (-0.82%)	⬇️

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[janosg]

Very nice. Thanks a lot!

Could you add quotes around the algorithms? i.e. "scipy_lbfgsb" instead of scipy_lbfgsb. I think that would make it more convenient if you really want to use the copied code.

[janosg]

Thank you very much @amageh. Great work as always!