schedule export: confirm before/after scheduling

[johanvdw]

cfr discussion on ml:

I have scheduled the talks int he Debuggers & Analysis devroom, in the
physicall room K4401 for the Saturday afternoon, starting from 15:00.
Everything looks like in the schedule editor. Yet, the schedule doesn't
show up at https://fosdem.org/2024/schedule/track/debuggers-and-analysis.

I think it's a bug, as I have nearly the same issue with the "FOSS on Mobile Devices" devroom: only talks which were confirmed after being scheduled appear at https://fosdem.org/2024/schedule/track/foss-on-mobile-devices/

[johanvdw]

this may be similar:
taking a screenshot for reference

[johanvdw]

releasing solves this, so let's make a release for every website build, the code is ready anyway