List and reorganise Tempo HTTP API

[annanay25]

Over time we have added a lot of endpoints to Tempo's HTTP API, including /metrics /shutdown /config /memberlist etc. While a few of these provide information that is useful in debugging and monitoring, there are others that are used to perform administrative tasks, for instance the shutdown one, and should probably not be defined at root (/). As we start working towards a stable release, we should attempt to

• add an "admin" endpoint that lists all the endpoints exposed by the target module
• decide on an API nomenclature and move the endpoints to locations that make sense in terms of functionality

[tharun208]

@annanay25 I like to work on this

[annanay25]

Its yours! @tharun208

[josephwoodward]

@tharun208 Are you working on this? Otherwise I'm happy to pick it up.

[tharun208]

@josephwoodward yes, I am working on this

[josephwoodward]

@tharun208 Okay, no problem 😁 Thanks for getting back to me.

[josephwoodward]

@tharun208 How have you been getting on with this? Need a hand?