Add q2-feature-classifier as an option

[cjfields]

This seems to work pretty well with PacBio and Loop full length 16S runs and the full-length trained data. On our local cluster using the QIIME2 output from the pipeline:

module load QIIME2/2020.6
qiime feature-classifier classify-sklearn --i-classifier QIIME2/silva-138-99-nb-classifier.qza --i-reads sequences.qza --o-classification tax_final.qiime2.qza --p-n-jobs $SLURM_NPROCS
qiime tools export --input-path tax_final.qiime2.qza --output-path tax_final.qiime2

[cjfields]

Note that a dada2 Silva database is also now available for this step, which works well with internal data (both Loop and PacBio).