build(python): avoid using requirements.in (#266)

[mdonadoni]

Pass the correct extras to pip-compile instead of duplicating
requirements in requirements.in.

[mdonadoni]

As far as I can tell, these extras were created in the past to avoid installing some libraries when building the docs, as they were not compatible with Python/system packages available on ReadTheDocs.

See for example:

• reanahub/reana-job-controller@2fa5221
• reanahub/reana-workflow-engine-snakemake@939ae77
• e9f803f

Note that with ReadTheDocs v2 it's now possible to choose the version of the Python interpreter and to install APT packages, see: https://docs.readthedocs.io/en/stable/config-file/v2.html#build-apt-packages

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 47.89%. Comparing base (b6c0503) to head (b9deced).
Report is 1 commits behind head on master.

Additional details and impacted files

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##           master     #266   +/-   ##
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  Coverage   47.89%   47.89%           
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  Files           6        6           
  Lines         261      261           
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  Hits          125      125           
  Misses        136      136           

[tiborsimko]

As far as I can tell, these extras were created in the past to avoid installing some libraries when building the docs

Also for the app functionality, to have the basic libraries in, because naked pip-compile call wouldn't bring them in.

And having unique requirements.in across packages seemed advantageous because one could then use the very same CLI command in all repositories regardless of whether this or that repository need this or that extra. (That knowledge is remembered in the in file, so the CLI call could be the same across the ecysystem)

However, we are not using this feature much, only three components or so, hence we could indeed remove these in files for simplicity, at the price of having to be strict to always pass the proper extra arguments in each concrete repository when we are running pip-compile by hand. (And at the gain of not having to specify jq version in two places.)