Add columns for sessions/talk types to program sheets (docs)

[splattater]

• add columns for tutorial, hackathon, talk, workshop, discussion ... in google docs sheets
• adjust cmem pipeline
• show type in program tables

[white-gecko]

should this be one "type" column with the values "tutorial, hackathon, talk, workshop, discussion"?

[white-gecko]

@splattater

should this be one "type" column with the values "tutorial, hackathon, talk, workshop, discussion"?

[splattater]

@white-gecko Yes, one column should be easier to handle in cmem. Maybe the values can be restricted to the values we need.