Tweak some asset editing and expose excerpt from html

Fixes #1996
Work around HPC's new qsub -d bug

This will break with weird characters in $PWD but hopefully that won't
happen.
Don't check permissions on transcode return

By setting superuser in LocalAuth
Add email to SiteParty.json with appropriate permission

Fixes #2004
Remove duplicate email field

This is rather inefficient, but oh well.  See #2004
Allow as-in race ingestion (no validation)
More flexible date parsing for ingest, and optional bday flag
Allow multiple sessions per participant by date

Weakens checking but really is necessary