[DBaaS] Add search and filter options for kubernetes and DB clusters

User Impact/Reason:

For users that will have a large number of Kubernetes and/or DB clusters, will have an option to search for or filter out clusters according to what they want. 

Improvement required:

Adding a standard search option for both kubernetes and DB clusters.

Adding filters, such as:
1. For DB clusters: DB type, Number of Nodes, exposed, date created etc.

2. For kubernetes clusters: Status (Active, Provisioning, Unavailable etc), having PXC operator version v.1.11.0 or MongoDB v.1.12.0 etc., available for update. 

As discussed with andrew.minkin, we will have pagination for the clusters as well, with that, if we can have an option to edit the count limit (50 or 100 or X number of clusters visible on a single page), that will provide the user with a better experience.