Context:

Add a public API to use the existing export dashboard definition functionality. We can reuse the accessToken added for json export of report results.

Endpoint Details:
POST /public/export/dashboard/definition/json
Takes json array of dashboardIDs, returns json array of dashboard and report definitions
Uses same accessToken as json export of report results

AT:

• a public API exists which takes a set of dashboard IDs and returns dashboard definitions
• this API requires a valid json export token (defined in config, same as for report result json export)