Changes include Metadata support, Upload tosca policy model and Loop Template

CLAMP Metadata support to parse policy_model_type, acronym and clamp_possible_values from the Tosca Policy Model
UI and Backend changes to support Loop Template
Backend APIs for Dictionary referenced in the Tosca Policy Model.
Upload Tosca Model UI changes to allow user to upload policy models.
DB Schema changes for the Loop Element Model and updated schema for the Dictionary
Added Jest test cases and snapshots
checkstyle issues fix and Junits

Issue-ID: CLAMP-580

Signed-off-by: ash74268 <ashwin.shyam.sharma@att.com>
Change-Id: I57521bc1c3afaf4ca5a2acf4c59823df05fd4cd6
Signed-off-by: ash74268 <ashwin.shyam.sharma@att.com>