Configurable Overview page

[gdubicki]

Implements #544 and #533.

Firstly I moved the "population" - number of nodes - to the same row as other metrics that show the number of nodes in various states.

Then I added 2 new configuration settings to allow disabling 2 sections of that page:

• RESOURCES_STATS_ENABLED
• NODES_STATUS_DETAIL_ENABLED

Both are set to True by default for backward compatibility.

I also organized the docs for all the settings in the README.

[gdubicki]

A screenshot showing the updated front page with both sections disabled. Note where the "total population" metric is located now.

[gdubicki]

Hm, I need to fix the tests...

[gdubicki]

I also forgot to update def index(env), so we still actually get the data that we do not show in the template... 🤦

[gdubicki]

Oups, disabling NODES_STATUS_DETAIL_ENABLED breaks failed/pending/changed/unreported metrics...

[sebastianrakel]

This is fine, but the decreasing test coverage should be fixed

[gdubicki]

Thanks @sebastianrakel , but I have to make it work with RESOURCES_STATS_ENABLED=True and NODES_STATUS_DETAIL_ENABLED=False without actually all the processing that would be done if NODES_STATUS_DETAIL_ENABLED=True.

[sebastianrakel]

After a chat with @gdubicki, we will close this pull request in favor of #639