EVEREST-1814 add creating state

[oksana-grishchenko]

Add "Creating" DB status

Problem:
EVEREST-1814

Problem:
The DB can be in an ‘unknown’ state for a couple of seconds and we didn't want to show that to the user.

Solution:

The upstream operators have the different statuses when a cluster is being created:

• pxc - "unknown"
• psmdb - ""
• pg does not have any empty status.

So the upstream statuses are different although Everest maps the DB status to the upstream cluster status 1:1. There is no point so far to create a separate mapping for each upstream operator only because we want to unify AppStateCreating, so in this PR the Everest operator unifies the "" and "unknown" statuses into the "creating" status.

Related PRs:

• EVEREST-1714 DB Creating status everest#1084

CHECKLIST

Helm chart

• Is the helm chart updated with the new changes? (if applicable)

Jira

• Is the Jira ticket created and referenced properly?

Tests

• Is an Integration test/test case added for the new feature/change?
• Are unit tests added where appropriate?