This task involves removing the autoconf/libtool and SCons build systems in WiredTiger.

The CMake build system is to become the main driver for POSIX and Windows builds. We now want to deprecate support for the old build systems and remove them from future releases on the WiredTiger standalone repository.

We want to make sure this ticket is done at an appropriate time, as to not break people's workflows and at a time the CMake build system is in a stable state (e.g most major bugs and issues have been ironed out). 

Definition of Ready:

• Evergreen builds updated to use CMake as the main compilation driver (removing references and usages of autoconf and SCons)

Definition of Done:

• Removed autoconf and SCons related build system files e.g. build_posix and build_win.
• Audit Doxygen documentation and ensure any lingering references to autoconf and SCons are updated to CMake documentation.
• Ensure CMake build still works as expected.
• Ensure there no breakage to MongoDB builds