forward html-messages properly (#2151)

* add failing tests for forwarding html-mails

* let MsgId.get_html() return an option

* write html-part to local database on forwarding

* add html-part to forwarded non-dc messages

* read HTML-parts from encrypted messages

* avoid clone()

* Received:-header is no longer needed since #2152

* Update src/html.rs

Co-authored-by: Floris Bruynooghe <flub@devork.be>

* Update src/html.rs

Co-authored-by: Floris Bruynooghe <flub@devork.be>

* Update src/mimeparser.rs

Co-authored-by: Floris Bruynooghe <flub@devork.be>

* prefer 'orig' over 'org' as abbreviation for 'original'

* improve comment on tests

* prefer 'try_into()' over 'as u32' to avoid panics on bad data

* simplify ffi

Co-authored-by: Floris Bruynooghe <flub@devork.be>

src/chat.rs

@@ -1060,6 +1060,12 @@ impl Chat {
             EphemeralTimer::Enabled { duration } => time() + i64::from(duration),
         };
 
+        let new_mime_headers = if msg.param.exists(Param::Forwarded) && msg.mime_modified {
+            msg.get_id().get_html_as_rawmime(context).await
+        } else {
+            None
+        };
+
         // add message to the database
 
         if context
@@ -1078,10 +1084,12 @@ impl Chat {
                         hidden,
                         mime_in_reply_to,
                         mime_references,
+                        mime_modified,
+                        mime_headers,
                         location_id,
                         ephemeral_timer,
                         ephemeral_timestamp)
-                        VALUES (?,?,?,?,?,?,?,?,?,?,?,?,?,?,?);",
+                        VALUES (?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?);",
                 paramsv![
                     new_rfc724_mid,
                     self.id,
@@ -1095,6 +1103,8 @@ impl Chat {
                     msg.hidden,
                     msg.in_reply_to.as_deref().unwrap_or_default(),
                     new_references,
+                    new_mime_headers.is_some(),
+                    new_mime_headers,
                     location_id as i32,
                     ephemeral_timer,
                     ephemeral_timestamp
@@ -2738,7 +2748,8 @@ pub async fn forward_msgs(
             // we tested a sort of broadcast
             // by not marking own forwarded messages as such,
             // however, this turned out to be to confusing and unclear.
-            msg.param.set_int(Param::Forwarded, 1);
+            msg.param
+                .set_int(Param::Forwarded, src_msg_id.to_u32() as i32);
 
             msg.param.remove(Param::GuaranteeE2ee);
             msg.param.remove(Param::ForcePlaintext);