extendable/configureable session times

[jsaalfeld]

When you are in a long talk, like the evening/late night talks, it appears, that after some time you got kicked out of your session. You can still write subtitles, but others in the channels cant see them. When you reload the page, you get a "session expired" notification. You have to log in again to subtitle further.

PS: maybe related to #91

[smotchkkiss]

I opened #91 and we’re pretty sure right now that its the same problem – people didn’t re-login before their shift without noticing their sessions were expired, because they could still write.