feat: migrate proxy sidecar injection and add Deployment proxy reconc…

[Vaishnav88sk]

This PR migrates the Kubernetes admission controller logic for injecting the Reshapr proxy sidecar from the reshapr repository to reshapr-controllers, fulfilling the architectural requirements outlined by maintainers.

Fixes #4

I would like to hear your thoughts on this. I have made chnages according my understandings. If any chnages, please let me know!

[lbroudoux]

It looks great! Thanks @Vaishnav88sk for pushing this one. I have only one comment on the default namespace, though. Can you check that one?

[Vaishnav88sk]

@lbroudoux updated the files. I think it is good to go. 👍🏻

[lbroudoux]

Thanks for the contribution!
One thing I'm not 100% sure of at the moment is the location of the DeploymentProxyProcessor. Sure: it's an operator but I wonder if it wouldn't make more sense to integrate it within the admission part so that it will be shipped within the same container image. I had in mind that operator was much more dedicated to the lifecycle of the CR to be used by a regular user...
What do you think?

[Vaishnav88sk]

I originally placed it in the operator module because it uses the Reconciler pattern, but I totally agree that shipping the sidecar feature in a single container makes perfect sense.

Quick question: Moving it means we'll need to add the quarkus-operator-sdk dependency to the admission module. Are you okay with the admission module taking on that dependency?"

[lbroudoux]

Quick question: Moving it means we'll need to add the quarkus-operator-sdk dependency to the admission module.

Yes you're right.

Are you okay with the admission module taking on that dependency?"

Yes, I think we already have part of the operator-sdk as dependencies.

We can manage that in the future. Let's close this PR and associated issue for now and make some progress on the reconciliers.