Add UI durability minimum level support to bucket creation

For the "Add Data Bucket" dialog please add support for bucket durability levels. This is for Couchbase buckets. Use field title "Durability Level" and allow clicking of one of the following buttons:

• None (default)
• Majority
• Majority and persist to active
• Persist to majority

The selected item above should be passed in the bucket creation params as
durabiltyLevel=

.

Note all the names are subject to change...there's currently differences in the PRD and kv code. But the logic shouldn't have to change once the final terms are determined.