Create widget json for pivot plugin

Please add details to the Jira on what widgets are being implemented. Also please add corresponding PRs to the jira

PR:
Pivot columns widget added- a widget as a combination of KeyValueDropdownRow and InputFieldDropdown named as InputKeyValueDropdown, where as a key we get the data from input schema and set them in the dropdown, and as a value, we have values separated with delimiter comma.

6.3 -