Continued test framework development

• Add target to generate Sail log and RVVI trace
• New top-level Makefile to compile all tests
• New top-level python entry point
• New config system for test framework
• UDB added as a submodule for use by the test framework
• Better dependency tracking
• Separate common tests from config specific ones
• Add CI to generate, compile, and run tests for every PR
• Produce objdump for each test if an objdump executable is specified in the config file
• Support generating tests and Makefiles for multiple configs. A top-level Makefile is created so tests for each config can be compiled in parallel.
• Add targets to generate UCDBs and coverage reports