Set `rfc724_mid` in `Message::new()`, `Message::new_text()`, and
`Message::default()` instead of when sending the message. This way the
rfc724 mid can be read in the draft stage which makes it more consistent
for bots. Tests had to be adjusted to create multiple messages to get
unique mid, otherwise core would not send the messages out.
fetch_existing option is not enabled in existing clients
and does not work with encrypted messages
without importing the key into a newely created account.
SecureJoin and importing a vCard are the primary
ways we want to support for creating contacts.
Typing in an email address and relying on Autocrypt
results in sending the first message unencrypted
and we want to clearly separate unencrypted and encrypted
chats in the future.
To make the tests more stable, we set up test contacts
with vCards as this always immediately
results in creating a single encrypted chat
and this is not going to change.
