Flesh out workers subcommand

[in03]

Let's add a command that allows us to run the worker compatibility check without actually queuing.
If we rework the commands and subcommands, etc, we can structure it like this:

rprox workers
(Always show compatibility breakdown,
show subcommand help if no further commands or options)

20 workers are compatible.
2 workers are incompatible and cannot be used by this version of Resolve Proxy Encoder.
To use them, update 'Editing Machine 1', 'Editing Machine 2' to '9f5aa99'.

Available subcommands:
- shutdown
- launch
- dashboard

And when all workers are compatible:

rprox workers

All 20 workers found are compatible.

Available subcommands:
- shutdown
- launch
- dashboard

Maybe even use this in other ways?

rprox workers shutdown --incompatible

Are you sure you want to shutdown these incompatible workers [y/n]?
- Editing Machine 1
- Editing Machine 2

y

Shutdown 2 incompatible workers.

Some others:

rprox workers launch 5
rprox workers launch 5 --dry-run
rprox workers shutdown all
rprox workers dashboard