Use multi-character config keys to fix error with snakemake v8.17.0

[lcoombe]

• With v8.17.0 of snakemake, was getting this error:

  
  snakemake -s /Users/lcoombe/Documents/GSC/miniconda3/envs/test/bin/ntsynt_run_pipeline.smk -p --cores 12 --config references='['celegans-chrII-III.fa', 'celegans-chrII-III.A.fa']' k=24 w=1000 t=12 fpr=0.025 prefix=celegans-A-ntSynt w_rounds='100 10' indel_merge=500 collinear_merge=3000 block_size=500 common=True simplify_graph=True benchmark=False dev=False --resources load=2 --rerun-trigger mtime 
  Traceback (most recent call last):
  
  File "/Users/lcoombe/Documents/GSC/miniconda3/envs/test/lib/python3.12/site-packages/snakemake/cli.py", line 1998, in args_to_api
  config=parse_config(args.config),
         ^^^^^^^^^^^^^^^^^^^^^^^^^
  
  File "/Users/lcoombe/Documents/GSC/miniconda3/envs/test/lib/python3.12/site-packages/snakemake/cli.py", line 256, in parse_config
  raise ValueError(

ValueError: Invalid config definition: Config entry must start with a valid identifier.

* Looks to be related to single-character config keys not being supported in this new version
* As a workaround, used multi-character keys for all parameters to the snakemake file
  * The `ntSynt` usage itself is unchanged - only a change under the hood