feat: refactor ingress controller build / push process

[qdzlug]

Is your feature request related to a problem? Please describe.
The current process is tied to the use of ECR as a container registry.

Describe the solution you'd like
The build process should handle:

• Build / pull plus enabled IC
• Build / pull standard IC
• Build / pull upstream IC (potentially?)

Additionally, it should be able to use any registry for pushing the resulting artifact(s).

This solution should also include necessary connectors for the IC deployment process (see #80 for details on some of the issues there)

Describe alternatives you've considered
Currently using the JWT and the NGINX corp repo, but this doesn't include all use cases.

Additional context
None.

[qdzlug]

This is closed by #167