move ASM strings to core, point to "Add Second Device" (#6777)

this PR moves now advanced/unsupported ASM strings to core, removing
work from translations, esp. as another hint is added which would
require retranslations. it is better to have that just in english, it is
a nerd feature anyways.

moverover, this PR removes special rendering of ASM in the summary,
which might be confusion, but mainly it is now unneeded, dead code

i'll do another android PR that will point to "Add Second Device"
already on ASM generation EDIT: done at
https://github.com/deltachat/deltachat-android/pull/3726

targets https://github.com/deltachat/deltachat-desktop/issues/4946

src/stock_str.rs

@@ -95,14 +95,6 @@ pub enum StockMessage {
     #[strum(props(fallback = "Archived chats"))]
     ArchivedChats = 40,
 
-    #[strum(props(fallback = "Autocrypt Setup Message"))]
-    AcSetupMsgSubject = 42,
-
-    #[strum(props(
-        fallback = "This is the Autocrypt Setup Message used to transfer your key between clients.\n\nTo decrypt and use your key, open the message in an Autocrypt-compliant client and enter the setup code presented on the generating device."
-    ))]
-    AcSetupMsgBody = 43,
-
     #[strum(props(
         fallback = "Cannot login as \"%1$s\". Please check if the email address and the password are correct."
     ))]
@@ -889,16 +881,6 @@ pub(crate) async fn archived_chats(context: &Context) -> String {
     translated(context, StockMessage::ArchivedChats).await
 }
 
-/// Stock string: `Autocrypt Setup Message`.
-pub(crate) async fn ac_setup_msg_subject(context: &Context) -> String {
-    translated(context, StockMessage::AcSetupMsgSubject).await
-}
-
-/// Stock string: `This is the Autocrypt Setup Message used to transfer...`.
-pub(crate) async fn ac_setup_msg_body(context: &Context) -> String {
-    translated(context, StockMessage::AcSetupMsgBody).await
-}
-
 /// Stock string: `Multi Device Synchronization`.
 pub(crate) async fn sync_msg_subject(context: &Context) -> String {
     translated(context, StockMessage::SyncMsgSubject).await