Fixes an issue where we'd be looking for custom healthcheck config on the
existing record object (from the provider) which would never have a custom
setup. Instead looking at desired lets us find what's actually configured to be
the case
- This reworks the CallerReference structure for Route53 health checks in a
non-backwards compatible way. This means records will create new healthchecks
for themselves which should be fine.
- Since we're pre 1.0, support has NOT been added to cleanup the old
healthchecks. That could be done reasonably easy, BUT we'd have to keep that
around forever. The hope is that the new ref format/usage will prevent this
problem going forward since enough info exists in the ref to identify things
fully. :fingers_crossed:
- healthcheck GC is much cleaner and more robust thanks to ^
- overall the healthcheck management code is a bit easier to follow and more
robust now.
