Merge software/compilers with another category

[ptheywood]

The software/compiler catorgory was set up to match the module file structure on the machine itself, as the collection of modules are all C/C++/Fortran compiler toolchains, which set common environment variables such as CC and CXX and may be mutually exclusive.

However they are not the only forms of compiler on the system, i.e. rustc.

It might be an improvement to:

• Move the compilers/* pages into a development / devtools category with tools (with appropriate redirects)
  • Or rename compiles to C/C++/Fortran compilers?
• Add a page for C/C++, cross referencing the available compilers and outlining any Power9 specific options?
• Add a page for Fortran, cross refernecing the available compilers and outlining any Power9 specific options?

This will be worth discussing.