Simplify the inserting and processing of messages.

Message widgets are now inserted into the listView through the `rowsInserted` callback of the messages model.

Messages are processed in the GetMessagesTask and GetApplicationMessagesTask when fetching multiple new messages. Single new incoming messages are processed in ProcessMessageTask.

gotify_tray/utils.py

@@ -4,7 +4,10 @@ import re
 import subprocess
 
 from pathlib import Path
-from typing import Optional
+from typing import Iterator, List, Optional
+
+from gotify_tray import gotify
+from gotify_tray.database import Downloader
 
 
 def verify_server(force_new: bool = False, enable_import: bool = True) -> bool:
@@ -28,6 +31,14 @@ def verify_server(force_new: bool = False, enable_import: bool = True) -> bool:
         return True
 
 
+def process_messages(messages: List[gotify.GotifyMessageModel]) -> Iterator[gotify.GotifyMessageModel]:
+    downloader = Downloader()
+    for message in messages:
+        if image_url := get_image(message.message):
+            downloader.get_filename(image_url)
+        yield message
+
+
 def convert_links(text):
     _link = re.compile(
         r'(?:(https://|http://)|(www\.))(\S+\b/?)([!"#$%&\'()*+,\-./:;<=>?@[\\\]^_`{|}~]*)(\s|$)',