All previous Configure script options should be CMake configure options

[LegalizeAdulthood]

There's a bunch of stuff the previous Configure script did that aren't relevant anymore as we don't need to support all those weird unix variants from the early 1990s.

However, there's still a fair amount that are still relevant, relating to configuring the local news environment, default user settings and so-on.

All the relevant options need to be exposed as documented CMake cache variables and described in the INSTALL file.