* Fix issue with HDF5_VOL_ALLOW_EXTERNAL CMake variable
* Add initial API test workflow
* Initialize parallel testing with MPI_THREAD_MULTIPLE when testing API
* Add CMake variable to allow specifying a VOL connector's package name
* Remove call to MPI_Init in serial API tests
While previously necessary, it now interferes with VOL connectors that
may need to be initialized with MPI_THREAD_MULTIPLE
* Update VOL CMake for REST VOL
* Prevent linking static libs to VOLs
* index on fetch_local: 5c5c3f1505 Prevent linking static libs to VOLs
* index on (no branch): 9a36d3e7b1 On fetch_local: WIP:add source dir fetch option for vols
* Allow building of VOL from local source
* Move LOCAL_DIR option to HDF5_VOL_ALLOW_EXTERNAL
* Remove macros from api tests (#2929)
* Remove macros and undefined callbacks (#2959)
* Remove remaining macros from H5_api_tests_disabled.h (#2968)
* Put some vol capability checks in testpar tests and remove remaining warnings (#2995)
* API tests datatype generation cleanup
* Clean up API tests' random datatype generation and fix bug with enum
datatype generation
* Init parallel API tests with MPI_THREAD_MULTIPLE
* HDF5 API tests - Check VOL connector registration
* Determine whether a VOL connector failed to load before running API
tests
* Cleanup some usages of H5VL_CAP_FLAG_CREATION_ORDER in API tests
* Remove some now-unused macros from H5_api_tests_disabled.h
* Enable HDF5 API tests by default
* Implement CMake option to install HDF5 API tests
* Check for invalid AAPL from H5Acreate
* Enable building of VOL connectors alongside HDF5 in CMake
* Prepend CMake VOL URL option indices with 0s so they come in order
* Don't turn on API tests by default yet
* Document VOL connector FetchContent functionality
* Add release note for API test updates
* Only install testing library if API tests are installed
* Fix grammar
