core: signed messages status (#6699)

* XOcore: signed messages status

* remove empty lines

Co-authored-by: Evgeny <evgeny@poberezkin.com>

* EOL

* only mark verified as verified

* update API types

* todos

---------

Co-authored-by: Evgeny @ SimpleX Chat <259188159+evgeny-simplex@users.noreply.github.com>

src/Simplex/Chat/Store/Postgres/Migrations/chat_schema.sql

@@ -344,7 +344,7 @@ CREATE TABLE test_chat_schema.chat_items (
     group_scope_group_member_id bigint,
     show_group_as_sender smallint DEFAULT 0 NOT NULL,
     has_link smallint DEFAULT 0 NOT NULL,
-    msg_signed smallint DEFAULT 0 NOT NULL
+    msg_signed text
 );