feat: Add crossMap3-based method rules to metaGEM.sh parser

[franciscozorrilla]

Currently the parser only supports submitting jobs through the crossMap-based method, i.e. N (= number of samples) jobs submitted cross-mapping each set of paired end reads to the focal sample assembly in series for small-medium datasets.

Still need to add the wildcard expansion strings for crossMap3-based method, i.e. where N x N individual jobs are submitted for each individual cross-mapping operation using kallisto for large datasets. Need to add parser support for rules kallistoIndex, crossMap3, gatherCrossMap3, kallisto2concoctTable, etc. in the metaGEM.sh parser and ensure that there are not rule dependency conflicts (e.g. multiple rules generate same output so Snakemake gets confused).

[franciscozorrilla]

Could be easiest to use the Snakemake modularization feature to call on rules from external snakefile to avoid rule dependency conflicts