Merge Joost's gen-pygeoapi-config branch into master

[anthonyfok]

This is the gen-pygeoapi-config work that Joost authored in March 2021.

The original gen-pygeoapi-config branch is duplicated as gen-pygeoapi-config--for-master and is rebased against the master branch as of today (June 3, 2021), with flake8 warnings fixed.

This (partially?) resolves works towards accomplishing #73.

Hey Joost, if you are reading this:

• Please correct me if I am wrong, esp. regarding this PR's relation to Centralize the pygeoapi configuration file #73.
• I would love to have this "rebased and merged" into master before Pipeline optimization (Sprint 34–36) #105.
• Last but not least: Sorry for jumping the gun! 😅

[jvanulde]

I am not convinced that this will be the way we generate the configuration in the future but let's at least bring it in so that we don't lose it in some obscure branch.

[anthonyfok]

Thanks Joost!

I am not convinced that this will be the way we generate the configuration in the future but let's at least bring it in so that we don't lose it in some obscure branch.

Good point! I'll make a note of this at #73 for continued work in this area.