Index Template: Parse and validate mappings in template when it puts

Parse and validate mappings in template when it puts.

* parse and validate mappings in template using dummy index service
* return error if template include invalid mapping 
* Not support a partial template

Close #2415
Creating an index seems to have a number of things for mappings validation that would be hard to access outside of index creation. If you can validate with the index service, great.  But here I was just suggesting being a little more careful with the temporary index that was created, both for visibility and lifetime.