feat: allow the user to replace maps integration (#5678)

with this PR, when an `.xdc` with `request_integration = map` in the
manifest is added to the "Saved Messages" chat, it is used _locally_ as
an replacement for the shipped maps.xdc (other devices will see the
`.xdc` but not use it)

this allows easy development and adapting the map to use services that
work better in some area.

there are lots of known discussions and ideas about adding more barriers
of safety. however, after internal discussions, we decided to move
forward and also to allow internet, if requested by an integration (as
discussed at
https://github.com/deltachat/deltachat-core-rust/pull/3516).
the gist is to ease development and to make users who want to adapt,
actionable _now_, without making things too hard and adding too high
barriers or stressing our own resources/power too much.
note, that things are still experimental and will be the next time -
without the corresponding switch being enabled, nothing will work at
all, so we can be quite relaxed here :)

for android/ios, things will work directly. for desktop, allow_internet
needs to be accepted unconditionally from core. for the future, we might
add a question before using an integration and/or add signing. or sth.
completely different - but for now, the thing is to get started.

nb: "integration" field in the webxdc-info is experimental as well and
should not be used in UIs at all currently, it may vanish again and is
there mainly for simplicity of the code; therefore, no need to document
that.

successor of https://github.com/deltachat/deltachat-core-rust/pull/5461

this is how it looks like currently - again, please note that all that
is an experiment!

<img width=320
src=https://github.com/deltachat/deltachat-core-rust/assets/9800740/f659c891-f46a-4e28-9d0a-b6783d69be8d>
&nbsp; &nbsp; <img width=320
src=https://github.com/deltachat/deltachat-core-rust/assets/9800740/54549b3c-a894-4568-9e27-d5f1caea2d22>

... when going out of experimental, there are loots of ideas, eg.
changing "Start" to "integrate"

src/webxdc.rs

@@ -74,6 +74,9 @@ pub struct WebxdcManifest {
     /// Optional URL of webxdc source code.
     pub source_code_url: Option<String>,
 
+    /// Set to "map" to request integration.
+    pub request_integration: Option<String>,
+
     /// If the webxdc requests network access.
     pub request_internet_access: Option<bool>,
 }
@@ -100,6 +103,9 @@ pub struct WebxdcInfo {
     /// URL of webxdc source code or an empty string.
     pub source_code_url: String,
 
+    /// Set to "map" to request integration, otherwise an empty string.
+    pub request_integration: String,
+
     /// If the webxdc is allowed to access the network.
     /// It should request access, be encrypted
     /// and sent to self for this.
@@ -920,6 +926,9 @@ impl Message {
             }
         }
 
+        let request_integration = manifest.request_integration.unwrap_or_default();
+        let is_integrated = self.is_set_as_webxdc_integration(context).await?;
+
         let internet_access = manifest.request_internet_access.unwrap_or_default()
             && self.chat_id.is_self_talk(context).await.unwrap_or_default()
             && self.get_showpadlock();
@@ -944,7 +953,12 @@ impl Message {
                 .get(Param::WebxdcDocument)
                 .unwrap_or_default()
                 .to_string(),
-            summary: if internet_access {
+            summary: if is_integrated {
+                "🌍 Used as map. Delete to use default. Do not enter sensitive data".to_string()
+            } else if request_integration == "map" {
+                "🌏 To use as map, forward to \"Saved Messages\" again. Do not enter sensitive data"
+                    .to_string()
+            } else if internet_access {
                 "Dev Mode: Do not enter sensitive data!".to_string()
             } else {
                 self.param
@@ -957,6 +971,7 @@ impl Message {
             } else {
                 "".to_string()
             },
+            request_integration,
             internet_access,
             self_addr,
             send_update_interval: context.ratelimit.read().await.update_interval(),