Enable status subresource for instance CRD

[alenkacz]

What this PR does / why we need it:
Currently, our Instance CRD contains status but we don't have status subresource enabled. That means that we're vulnerable to this behavior described in API conventions:

The PUT and POST verbs on objects MUST ignore the "status" values, to avoid accidentally overwriting the status in read-modify-write scenarios. A /status subresource MUST be provided to enable system components to update statuses of resources they manage.

Otherwise, PUT expects the whole object to be specified. Therefore, if a field is omitted it is assumed that the client wants to clear that field's value. The PUT verb does not accept partial updates. 

Fixes #1043