Declaring remediation taint with NoExecute effect to drain pods and not schedule them again on the unhealthy node

Remove node taint when a CR is about to be deleted using a finalizer

We need to add two new rbac rules: delete, and patch for adding and removing taint on a cluster node

The E2E test is redundant after medik8s#48 PR, and it also fails here when we try to add/remove taint for a node which doesn't exist - dummy-node

Apparently a taint is considered unique by key:effect, reagrdless of the taint's value -  if the two taints share the same key:effect. then are considered equal. We modify the taint's key to be unique and not similar to SNR's remediation taint

The API server is updating taints as well while nodes get healthy/unhealthy, so patch can overwrite changes made by API server

When CR/node is invalid. then there is no need to add/remove finalizer and taints

Test it on valid and invalid CRs

Share variables and lowercase var name