feat: better registry handling ✨

[liquidiert]

• add registry url cli option for easy registry change
• fix service annotations
• fix replacement of kwargs with empty dict by filtering only the empty values

closes #703
closes #670

[Schille]

With a custom registry link, you must also pass this as env for Stowaway. Otherwise, you'll end up with this component pulled from the default registry:

gefyra/operator/gefyra/configuration.py

Lines 7 to 10 in 9fcbf7e

	self.STOWAWAY_IMAGE = config(
	"GEFYRA_STOWAWAY_IMAGE", default="quay.io/gefyra/stowaway"
	)
	self.STOWAWAY_IMAGE_PULLPOLICY = config(

Look for the workload definition of Stowaway in the Operator code to set this env (it's currently not specified and hence uses the default).

[crkurz]

@Schille ,
it appears this will also solve packet drops due to MTU size when used with CISCO VPN, which is terrific! Thank you!

Nit: for tracking do we need a ticket for MTU size problem and should that ticket be linked to this PR?

[crkurz]

@Schille ,
fyi, I have filed GEFYRA-738 for MTU issue. This might need to be linked to this PR.