feat: implement v1beta2 api

[shreddedbacon]

Checklist

• [ ] Affected Issues have been mentioned in the Closing issues section
• [ ] Documentation has been written/updated
• [ ] PR title is ready for changelog and subsystem label(s) applied

Introduces new v1beta2 api which has less fields than v1beta1, mostly due to not populating the messaging structures into the api.

It removes the pending message functionality from v1beta2 entirely, as this functionality never worked properly.

v1beta1 is still supported if they are detected in a cluster, but all new builds when received will be created as v1beta2 builds. v1beta1 builds will be removed once they're completed though.

Supporting chart changes https://github.com/uselagoon/lagoon-charts/pull/688

[shreddedbacon]

This will be released as v0.20.0 of remote-controller