Add a validation check for the projected pod names length

[adejanovski]

Pod names are limited in length and we should make sure to fail fast when we project an overflow.
The following elements must be accounted for:

• cluster name
• dc name
• rack name
• -sts-??? part

The validation webhook should reject any attempt to create a cluster that would create pod names which are too long.

Definition of Done

Beta Give feedback

1. Creating a cluster/dc/rack that generates pod names too long