Allow to override the pull policy of the controller in 'kudo init'

[nfnt]

What this PR does / why we need it:
This makes it easier to deploy KUDO in test environments where a KUDO image is available in the cluster but not in any repository.

[ANeumann82]

Nice, i've had to add that in my init --upgrade branch as well, but better to have it here in a separate PR.

I would prefer a more distinctive name, but that's not a blocker for me.

The missing validation for the pullPolicy is though ;)

[zen-dog]

I'm not sure if we want to add flags to control individual fields of the output YAML even if it gets rid of the sed in tests 🤔 But it certainly needs more validation.

[ANeumann82]

I'm not sure if we want to add flags to control individual fields of the output YAML even if it gets rid of the sed in tests 🤔 But it certainly needs more validation.

We actually need this. For these tests it works with the sed, but only because we "export" the yaml before installing it. It would actually be better to use the real kudo init for installation, and in that case we can't use sed. (For the kudo init --upgrade the sed variant isn't even possible)