Merge a developer project

Merges a developer project. This operation runs ansynchronously and merges the channels, content types, documents, pages and resource bundles. Merge operation pushes the changes to the core project. In case a conflict happens during the merge operation, then the operation can be tried again after resolving the conflicts manually. The result of the operation could be seen by calling the GET endpoint. Only users with 'Site Admin' role can run the merge operation.