New Component for Indexing JSON

Bulk indexing of field already converted to JSON
Create README.md
Merge pull request #2 from DerekF35/master

New Component for Indexing JSON. This will accept prepared JSON string and index it to ES. JSON string can be created using tMustache.

@Derek, tElasticsearchIndex handles this in following way:
1. Output schema of component has only one field of type String and not marked as key.
2. If, above condition is true then treat this only field as JSON string to index and use corrosponding API.

This convention does not look intuitive. This new component will make it explicit and hence, intuitive.