[3.0] Rename commands from `api:` to `apidoc:`

[shalvah]

Dingo already uses the api namespace, and since it's likely to be used alongside this package, it's best to avoid any possibility of conflicts, as well as separate the two visually.

[devjoca]

I can take care of this

[karkowg]

I don't know how @jopereyral changes did not break tests but I've updated the command references there and also in the docs.