feat: key-contacts

This change introduces a new type of contacts
identified by their public key fingerprint
rather than an e-mail address.

Encrypted chats now stay encrypted
and unencrypted chats stay unencrypted.
For example, 1:1 chats with key-contacts
are encrypted and 1:1 chats with address-contacts
are unencrypted.
Groups that have a group ID are encrypted
and can only contain key-contacts
while groups that don't have a group ID ("adhoc groups")
are unencrypted and can only contain address-contacts.

JSON-RPC API `reset_contact_encryption` is removed.
Python API `Contact.reset_encryption` is removed.
"Group tracking plugin" in legacy Python API was removed because it
relied on parsing email addresses from system messages with regexps.

Co-authored-by: Hocuri <hocuri@gmx.de>
Co-authored-by: iequidoo <dgreshilov@gmail.com>
Co-authored-by: B. Petersen <r10s@b44t.com>

src/sql/sql_tests.rs

@@ -179,9 +179,7 @@ async fn test_migration_flags() -> Result<()> {
     // as migrations::run() was already executed on context creation,
     // another call should not result in any action needed.
     // this test catches some bugs where dbversion was forgotten to be persisted.
-    let (recalc_fingerprints, update_icons, disable_server_delete, recode_avatar) =
-        migrations::run(&t, &t.sql).await?;
-    assert!(!recalc_fingerprints);
+    let (update_icons, disable_server_delete, recode_avatar) = migrations::run(&t, &t.sql).await?;
     assert!(!update_icons);
     assert!(!disable_server_delete);
     assert!(!recode_avatar);