We have a CSR authorizer plugin for calling to an IPC service. In this commit we add test implementation of such a service. We also remove the simple_csr_authorizer plugin and fold its functionality into the new test_csr_authorizer functionality.
This is part of the program to move REST services like bx509d out of kdc/.
Part of refactoring to split out bx509/bnegotiate, add a kadmin REST service, and move all of that out of kdc/.
