Advance dmi plugin to stub return diff. module set by using REST api (onap dmi plugin stub REST api specific to update static map that holds information of am handle per module set tag)

Existing DMI Stub

pre-defined nodes, which modules hardcoded based on name (prefix) of each like:
 bookStoreA (M1 & M2) No Tag
 bookStoreB (M1 & M2) No Tag
 bookStoreC (M1 & M2) No Tag
 

Does not allow for testing of upgrade  

Proposed :

1. Hard code module set responses based on Tag with modules
   1. NO Tag (M1 & M2)
   2. TagA  (M1 & M2)
   3. TagB  (M1 & M3)
   4. TagC  (M4 & M5)
2. Rename (json) repsonse files in stub after Tags
3. In memory map to associate a cm-handle(id) with a Tag. Empty by default
   1. Map<String,String> ModuleSetTagPerCmHandleId: (cmHandleId->ModuelSetTag)
4. Expose our own rest interface (undocumented on Stub only) to add /update ModuleSetTagPerCmHandleId entries
5. Rename existing hardcoded cm-handles so they don't seem associated by cm module sets. e.g. bookStore1, Bookstore2, Bookstore3
   1. by default each will NOT have a module set tag and therefore return modules M1 & M2
6. possible (test) use cases can now be supported
   1. assign Tag A to bookStore1 (no actually change of modules!)
   2. update bookstore2 to TagB (new but overlapping)
   3. update bookstore1 to TagB (existing)
   4. update bookstore3 to TagC (new, no overlap)
   5. etc.