Route documentation unit test

[edtanous]

Once #181 is resolved, it should be relatively straightforward to write a unit test that greps for BMCWEB_ROUTE instances, and verifies that we have a corresponding instance in the documentation. This should be a relatively easy script to write and put in the unit tests, so new routes without documentation are notified at compile time that they've forgotten their docs updates.

[edtanous]

Tried to execute on this recently, and it's very non-trivial.

Series working up to this is here:
https://gerrit.openbmc.org/c/openbmc/bmcweb/+/60832

and involved changes to the Redfish standard, as it didnt' model all URI routes in a consistent way.