C api and unit tests for vnf converter #121

Job	Run time
Build sdist and set version	34s
build-cpp-test-linux (debug, gcc)	4m 50s
build-cpp-test-linux (debug, clang)	2m 53s
build-cpp-test-linux (release, gcc)	6m 19s
build-cpp-test-linux (release, clang)	5m 13s
build-cpp-test-macos (debug)	2m 50s
build-cpp-test-macos (release)	3m 52s
build-cpp-test-windows (debug, msvc)	5m 49s
build-cpp-test-windows (debug, clang-cl)	7m 17s
build-cpp-test-windows (release, msvc)	5m 35s
build-cpp-test-windows (release, clang-cl)	7m 17s
Build and test in Conda (ubuntu)	57s
Build and test in Conda (windows)	3m 29s
build-and-test-python (linux-x64)	3m 51s
build-and-test-python (linux-aarch64)	6m 50s
build-and-test-python (macos)	3m 17s
build-and-test-python (windows)	6m 13s
publish-wheels	4s
	1h 17m 10s

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