Need a way to delete a single resource

[jessesuen]

A user hit an issue where an kubectl edit was performed from underneath argocd's kubectl apply. A field was added to selector.matchLabels. Because of this, kubectl apply did not remove this field (since it believed it to be defaulted by a controller), and the apply failed due to mismatched labels.

To handle issues like this, we additionally need a "replace" sync strategy, which will perform a kubectl replace instead of apply. This will also solve the problem when a user wishes to modify immutable fields (e.g. a service type needs to change from LoadBalancer)

[jessesuen]

This will be handled by the apply sync strategy with a force option. Which translates to kubectl apply --force

[jessesuen]

d633f6b adds the ability to supply --force when performing a sync.

[jessesuen]

Reopening. I incorrectly thought that after the addition of the --force flag, it would cover cases where the kubectl apply failed due to incompatible spec changes. However, it seems we still do not handle cases when we change a service from LoadBalancer to ClusterIP. For these types of situations, we really need kubectl replace.

[jessesuen]

Fixed