Feature: Setting number of workers per subscriber

[mhkarimi1383]

To suggest an idea or inquire about a new Message Broker supporting feature or any other enhancement, please follow this template:

Is your feature request related to a problem? Please describe.
I want to scale my subscribers/router separately (using the cli or decorator parameters)

Describe the solution you'd like
a cli arg for custom scaling option per router/subscribers by their name/func_namea

Feature code example
To help others understand the proposed feature, illustrate it with a FastStream code example:

faststream run --workers=router1:4,subscriber1:2
...

Describe alternatives you've considered
Creating multiple apps and running them separately

Additional context

Nothing