cleoc: Test cobra 'wiring' (parameter precedence, invocation of right subcommand)

The same thing also applies to cleosrv, but once it's solved for one it's easy to port to the other.

Right now only `cleoc.App` is being tested. But it also needs to be ensured that when calling a certain (sub-)command the right function is invoked and that parameter precedence works correctly, parameters are parsed etc.

Given that this cobra 'wiring' is rather simple, it's not very urgent. But it is an important part of the user experience, so it needs to work correctly.

Start with cleoc.App and its Cobra command wiring; identify the subcommand invocation and parameter parsing paths, then compare the corresponding cleosrv wiring. Add coverage for parameter precedence, parsed parameters, and dispatch to the correct function, with tests passing for both applications.

Written by the indexing model from the issue text.