Create a Controller for CDA Server info

[rma-rripken]

It would be helpful for debugging and other purposes if there was a CDA end-point that required authorization but was generally safe to call.

You could try to create a dummy location_group and then delete it again but thats annoying.
You could also try to write to catalog or some other non-writable end-point and look at what error code you get back. But that is sort of a hack.

I want a real end-point that requires auth and returns somewhat useful output that will also be obvious if its being cached.
The end-point should return some basic info like: A specific build number. Maybe even the commit hash if there is some way to get it. Not just "3.1". Maybe the OS and JDK versions. The native system clock (with tz) to the nearest second.

Then clients could call it on login. They could add the response in their own logs and if they hit a CDA bug we'd be able to correlate the bug report to source.

[MikeNeilson]

Given we have decided to include the actual CDA version info, we can start on this as appropriate.

I don't think we're currently embedding the commit hash in with the version, but it would be fairly trivial to add to the created resource file.

While the OS and JDK MUST NOT be available to non-authenticated, other information like the version and perhaps a matrix of capabilities, should be. See #959, see https://github.com/USACE/cwms-data-api/pull/959/files#diff-33016428fd988ae857301c2376c9e726680898c00a3250c9aaf47248b60d783b for current thoughts,

If you work on this, take the file from that PR and finalize it with the design choices made.