Move a helper to helpers
Bump version requirements
Filter out unwanted vcard presences
Comply with dev1 requiring starttls
Adjust h_ok_after_a_chat to superfluous presence stanzas

It might be better to insert explicit stanza discards in relevant
places than to use such a generic filter.
Conveniently convert string to server-side type
Explicilty discard vcard updates if mod_vcard_xupdate is on
Make server_requests_ack resilient to vcard updates
Leave out the unused Config param of discard_vcard_update
Don't rely on escalus_tcp stanza filtering
Discard vcard updates in resend_unacked_on_reconnection
Discard vcard updates in resume_session
Extract vcard_update stuff for reuse in another suite
Fail fast if the server string type is not known
Use server string type for resources in match specs