helmrepo: Add more reconciler design improvements

- Remove ArtifactUnavailable condition and use Reconciling condition to
  convey the same.
- Make Reconciling condition affect the ready condition.
- Introduce summarizeAndPatch() to calculate the final status conditions
  and patch them.
- Introduce reconcile() to iterate through the sub-reconcilers and
  execute them.
- Simplify logging and event recording
- Introduce controller-check/status checks to assert that the status
  conditions are valid at the end of the tests.
- Create variables for various condition groups: owned conditions, ready
  dependencies and ready dependencies negative.

Signed-off-by: Sunny <[email protected]>

Author: darkowlzz