Updates and overrides

[mdales]

This PR contains a number of things:

• The AOH code is now in a pip module, so we move to using AOH from pip rather than as a submodule
• There are now multiple scenarios for LIFE that people want, and it is expensive to run all of them if not needed. So now the only place the scenarios should be specified is at the top of run.sh or slurm.sh - it was in the generator scripts, but those scripts now take the scenarios required as arguments. We also will no longer generate habitat maps for scenarios that aren't being run.
• Because classification of real life systems is never perfect, allow a list of override species to be provided that will force those species to be included in the RedList dataset even if they'd otherwise be rejected due to filtering on category. Note species will still be rejected if the data is incomplete.