Supported compiler versions

[ian-ross]

@lrobion and I have been messing around with some build dependency things (in this PR: #69) and we've been having lots of fun testing things with all sorts of different compiler versions, mostly in the service of supporting back to GCC 11.2 (I'm being sarcastic, of course — it was no fun at all!).

We would like to suggest increasing the earliest supported compiler version to GCC 14. For people working within LAE, this shouldn't be a problem (mamba env create -n apcemm-build 'gxx>=14,<15' 'cmake>=3,<4' gets you a suitable environment). For the ICL cluster that @sdeastham was using last time we talked about this sort of thing, you can do sudo yum install gcc-toolset-14 and source scl_source enable gcc-toolset-14 to get the GCC 14 toolchain and everything works (I've tested it in an RHEL 8.5 VM, following the instructions in this comment).

Does anyone have any particular feelings one way or another about this?