Trigger prebuild reconciliation on changes to templates with prebuilds, and prebuilds settings

Currently, if a template version that defines some prebuilds configuration is pushed, that change doesn't immediately cause the reconciliation loop to iterate.

Likewise, if prebuilds are unpaused, prebuilds aren't reconciled until the next tick.

The default reconciliation interval is 60 seconds, so this is almost unoticeable, and unlikely to be an issue for the vast majority of users.

However, this may be confusing for users if they've modified the value of `CODER_WORKSPACE_PREBUILDS_RECONCILIATION_INTERVAL` to a larger value, and expect changes to prebuilds to be reflected sooner than the duration of that interval.

This issue was spun out from the TODO I noticed whilst testing prebuilds at scale:
https://github.com/coder/coder/blob/9298e7e073970011f7711cf37ffce5c5defe1a8d/enterprise/coderd/prebuilds/reconcile.go#L189