Store environment for LRPs and kpack builds in secrets

[danail-branekov]

This depends on #917

This is to adopt the fix from the issue above in Korifi. We should make sure that we inject environment in LRPs and kpack builds securely over secrets rather than a plain-text key-value pairs.

[gcapizzi]

I think this has already been done - @danail-branekov do you confirm?

[danail-branekov]

Actually, this issue is no longer relevant as we are not using eirini-controller anymore.

Other than that, we do use secrets to store environments already. Closing