[C2] Create default callback script that enables a videoconference system to send activity information back

[ywarnier]

[christianbeeznest]

It is implemented with this commit

d1c6c97

Thanks for confirmation.

[ywarnier]

We have to see if it's possible to receive this information back (through the callback script)

[ywarnier]

Not sure if we have any access validation on this? @christianbeeznest
(it otherwise looks good)