Clean up TopologyBuilder interface

[nathanwbrei]

My latest GPU offloading work is using custom topologies, which were never made part of the "public-facing" interface. This PR significantly improves the code quality of JTopologyBuilder, making it fit for public consumption, and laying the groundwork for defining custom topologies in the wiring file.

• Adds the long-awaited parameters: max_inflight_runs, max_inflight_timeslices, etc
• Fixes a long-standing problem where the user would have to manually size any queues and pools, rather than the capacity automatically propagating from max_inflight_events/etc.
• Adds automatic wiring validation via a JEventLevel annotation to every Port on every JArrow
• Adds a separate integration_tests binary for end-to-end testing, e.g. of custom topologies. Eventually a number of longer-running tests will be moved from unit-tests to here.
• Renames all member functions living under Topology/ to CamelCase, to be consistent with the rest of the JANA2 API.
• Fixes the missing encapsulation for JTopologyBuilder, and substantially reduces the amount of JANA2 knowledge necessary to use custom topologies
• Arrow ports can now be connected to queues and pools using only string identifiers, making it easy to represent in the wiring file