Relocate postman tests to correct submodule

[spbolton]

Now we have a separate dotcms-postman maven submodule and have fully moved away from gradle we should finally relocate the postman test sources from their current location within dotCMS/src/curl-test to dotcms-postman/src/main/resources and modify dotcms-postman/index.js to point to the new location.

We should notify all developers of this move so they can properly find existing and create their tests in the new location and identify any issues with the move. Maven modules should be as self-contained as possible and currently, the core module includes these files but does not use them.

Moving all in one PR should help reduce any issues with merging and history.