Extend SLURM parser to handle other unit prefixes.

- Add normalisation for G, T, and P.
Refactor test_slurm to reduce repition.
Expand unit test of slurm.py.

- Add testing for Queue, Site, MachineName and Infrastructure.
- Add more positive tests with larger memory values.
- Add negative tests for invalid memory values.
- Correct test for MemoryVirtual.
Correct SLURM parser.

- Add more supported unit prefixes.
- Make _normalise_memory more generic.
- Correct Queue to point to correct item in list.
Merge branch 'ggus_98409_cont' into dev