[docs] move contributing guide to docs and expand

[odow]

Closes #2675

I'll add a preview link once the build finishes.

Preview: https://jump.dev/JuMP.jl/previews/PR2743/developers/contributing/

[codecov]

Codecov Report

Merging #2743 (54ef2bd) into master (3100dee) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master    #2743   +/-   ##
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  Coverage   93.91%   93.91%           
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  Files          44       44           
  Lines        5568     5568           
=======================================
  Hits         5229     5229           
  Misses        339      339           

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[pulsipher]

This is a nice improvement. One suggestion would be to consider adding in a guide for using a GUI interface (e.g., VSCode) to contribute. This removes the need to use the terminal to check out environments and use git which lowers the barrier for contributors that are comfortable with creating Julia scripts, but not running shell commands. Sadly, my current workload won't permit me to make such a contribution myself.

One other suggestion, might be to mention that the tests can be run via including the runtests.jl file directly in an active REPL, so that they can be run multiple times much faster. Naturally, this needs to be done cautiously, but it is a nice way to debug tests quickly.

[odow]

One suggestion would be to consider adding in a guide for using a GUI interface

I haven't used the VS code interface, so I'm not in a strong position to do this. I suggest we leave as-is for this PR, and improve things later if there is demand.

[odow]

I'll merge for now. If anyone has other suggestions, please open a PR or an issue.