Drop Autotools support

[derobins]

These issues will probably be closed when we drop Autotools support in mid-November

[Dave-Allured]

"the CMake provided FindHDF5.cmake module expects an autotools built HDF5"
HDF5 Build with Shared Libraries in MSYS2 Causing CMake Errors #5175
Do not drop Autotools until this CMake problem is fixed.

[byrnHDF]

Using CMake built installs will have the config files and the find package call should be restricted to config mode and not allow module mode.