p2p/protocols: accounting metrics rpc (#18336)

* p2p/protocols: accounting metrics rpc added (#847)

* p2p/protocols: accounting api documentation added (#847)

* p2p/protocols: accounting api doc updated (#847)

* p2p/protocols: accounting api doc update (#847)

* p2p/protocols: accounting api doc update (#847)

* p2p/protocols: fix file is not gofmted

* fix lint error

* updated comments after review

* add account balance to rpc

* naming changed after review