Multicloud API updates for generic clouds

The multicloud adapter support added in Casablanca provided support for a 'template_type' of 'heat' and the 'template_data' contained a Heat Stack object.

For generic cloud support, addtional development is required to either identify another 'template_type' value to use and determine what the contents of the 'template_data' should be.

Or other changes to the API as appropriate.

Changes to the Multicloud API relevant for this Jira were made in this gerrit:  https://gerrit.onap.org/r/#/c/75851