CWL: provide additional cache for SV analysis on Arvados
CWL: provide additional cache for SV analysis on Arvados

Avoids slow runtime issues with SV callers that access a BAM file multiple
times (observed with manta).

lbeltrame/bcbio-nextgen,a113n/bcbio-nextgen,lbeltrame/bcbio-nextgen,chapmanb/bcbio-nextgen,a113n/bcbio-nextgen,vladsaveliev/bcbio-nextgen,lbeltrame/bcbio-nextgen,chapmanb/bcbio-nextgen,vladsaveliev/bcbio-nextgen,chapmanb/bcbio-nextgen,a113n/bcbio-nextgen,vladsaveliev/bcbio-nextgen