[pygeoapi] manager branch updates

[Tom Kralidis]

Hi all: the manager branch in pygeoapi has existed since June 2019 (OGC
API Hackathon in London) where Jorge and I worked on job management in
support of OGC API - Processes.  Following on, Richard has made some
excellent improvements as well as due diligence in keeping the branch up
to date with current master.

Having said this, EOX has started to use this branch and have contributed
numerous improvements (thanks Bernhard et. al.) in [2][3][4][5][6].

On my side, since the June 2019 OGC API Hackathon, I haven't found the
time to do a fulsome review of things, so I apologize for that.

It's time to sprint and put this branch into master.  If anyone is
interested/has
time, I'm proposing to work on this next week (16 December) to work on
cleaning up the branch in the hopes of making a final pull request.

Thanks

..Tom


[1] https://github.com/geopython/pygeoapi/tree/manager
[2] https://github.com/geopython/pygeoapi/pull/591
[3] https://github.com/geopython/pygeoapi/pull/590
[4] https://github.com/geopython/pygeoapi/pull/588
[5] https://github.com/geopython/pygeoapi/pull/589
[6] https://github.com/geopython/pygeoapi/pull/587