[FEATURE] Add "meta" command type

[tralph3]

I would like to add a command type that runs other conner commands. Problem is, I would need to wait for these async commands to finish to execute the next one, and I'm not aware of a way to do this right now.

[tralph3]

While there is a meta command type now, it doesn't wait for each command to finish before running the next one, unless the command is synchronous, in which case it's just part of the regular execution.

I would still like to have a variant that ensures commands are ran only when the previous one finishes.