protos(view): create unary equivalents of some streaming RPCs

[turbocrime]

we recently converted witnessAndBuild and authorizeAndBuild from unary requests to streaming requests, to allow the client to display progress data to the user

this isn't important to every use-case, and it may be beneficial in some cases or in unknown/novel contexts to issue a request without worrying about handling a stream

we should attempt to provide unary equivalents of methods that do not functionally require a streaming response, and fire-and-forget equivalents of methods that may be called only for a side-effect

this would mostly consist of adding endpoints, so is probably backwards-compatible