Is your feature request related to a problem? Please describe.

In order to configure script modules similarly to internal ones, they need to take command line arguments. These can get long, making the exec line unwieldy and less readable.

Why does polybar need this feature?

Ease of configuration; encouraging nicely integrated configurable third-party modules.

Describe the solution you'd like

I would suggest any attribute prefixed exec-arg get appended to exec (without 'exec-arg') with their value if non-empty, so that:

exec = something
exec-arg--verbose = true
exec-arg-v =

becomes:

something --verbose=true -v

Of course, there will always be exceptions where there's some non---prefixed arguments and they need to come in a certain order, but I think this would deal with a lot of cases.