no option to export within the flock client

[rhodey]

users can export their contacts through the android default "People" app but no default app provides export of calendars. the flock client should provide users with the ability to export their contacts and calendars to their SD card or another account on the phone.

[untitaker]

There is https://f-droid.org/repository/browse/?fdfilter=export&fdid=de.k3b.android.calendar.ics.adapter which can already do that for arbitrary calendars.