REST security roles redesign

When JBPM-5071 is resolved, there will be only two REST security roles that will make sense for KIE Workbench - rest-all and rest-project. Both of them will give a user the same access rights since Guvnor REST API will be the only remote interface in KIE Workbench 7.x. It makes no sense to have two roles with the same privileges so they should be merged into one. Or more fine-grained control over organizational units, repositories and projects can be designed but that is not necessary.

The other thing is that KIE Server will become the only option when it comes to remote process execution. However, in comparison with KIE Workbench 6.x, it does not provide different roles to restrict access control through remote APIs since kie-server is the only role that allows users to do anything. This needs to be changed in order to provide more fine-grained access control similar to the one in KIE Workbench 6.x.