GOCBC-1417: Add collections management support for PS

Motivation
-----------
We need to add support for doing scope & collections management
over protostellar.

Changes
-------
Add collections manager interface and core and ps implementations.

Change-Id: I7ba1b7b3fe48bf51ed482b58a85cdb56f28ca79f
Reviewed-on: https://review.couchbase.org/c/gocb/+/191361
Reviewed-by: Brett Lawson <brett19@gmail.com>
Tested-by: Charles Dixon <chvckd@gmail.com>

bucket.go

@@ -148,10 +148,9 @@ func (b *Bucket) ViewIndexes() *ViewIndexManager {
 func (b *Bucket) Collections() *CollectionManager {
 	// TODO: return error for unsupported collections
 	return &CollectionManager{
-		mgmtProvider: b,
-		bucketName:   b.Name(),
-		tracer:       b.tracer,
-		meter:        b.meter,
+		getProvider: func() (collectionsManagementProvider, error) {
+			return b.connectionManager.getCollectionsManagementProvider(b.Name())
+		},
 	}
 }