Federation Management methods (Big 4) support for centralized RTI

[timpokorny]

Summary

Port the existing distributed "Big-4" federation management methods from existing distributed operation to centralized. These are:

• createFederationExecution()
• joinFederationExecution()
• resignFederationExecution() and
• destroyFederationExecution()

Acceptance Criteria

Once complete, Portico shall:

• [x] support creating and joining a federation through the new central rtiexec
• [x] support resiging from and destroying a federation through the new central rtiexec
• [x] be able to confirm this functionality through the existing unit test suites
• [x] be able to confirm this functionality through the example 1516e federate

[timpokorny]

All done. Keeping this on base branch of port219-central-rti for now. Change is too disruptive to merge in small pieces.