Add endpoint for CDA software version that requires auth

[krowvin]

It is fairly difficult to determine what version you are on if you did not take a note of this prior. This goes for both the public and internal instances of CDA.

Admittedly this only really applies to developers and/or maintainers of the software.

Proposing we add an endpoint that returns the software version and potentially any other metadata about the install.

To prevent leaking version numbers it was suggested this be behind an endpoint that requires auth.

[DanielTOsborne]

Honestly, some version mechanism should be exposed, otherwise applications will have no way to know which API interfaces are available, or if they changed. This will become more of an issue as more applications, like CWMS, integrate CDA more thoroughly.

[rma-psmorris]

From a post-CURG discussion, recommended that this endpoint return in its payload an attribute that flags the CDA instance as being district local vs national so the calling application can discern between the two and operate accordingly.