[PSyData] Support non-local symbols in kernel extraxction for nemo and gocean

[hiker]

Currently the focus of kernel extraction is LFRic, especially the support for non-local symbols. This ticket is about porting these changes to support a generic PSyIR and gocean. There is a certain overlap with #2049, but besides refactoring code into a common base class other work might be required (e.g. https://github.com/stfc/PSyclone/pull/2367#discussion_r1467823116) - we need to check the call vs kernel handling, being aware that Kern might become a subclass of Kern).