Make Google Batch mount path configurable

[adamrtalbot]

New feature

It may be necessary to mount the gcsfuse at a different path to the default one (/mnt/disks/${bucketName}).

Use case

You might want to, I dunno, you do you man.

Suggested implementation

Make this static value configurable via the google.batch config scope:

nextflow/plugins/nf-google/src/main/nextflow/cloud/google/batch/GoogleBatchScriptLauncher.groovy

Line 45 in 6d3aa54

private static final String MOUNT_ROOT = '/mnt/disks'

[adamrtalbot]

This looks like it isn't possible with Google Batch API right now, waiting on confirmation from Google: #6058