[improvement][appimage] new initialization task that checks if the installed AppImage files have symlinks associated with

bauh/gems/appimage/util.py

@@ -0,0 +1,8 @@
+import os
+
+
+def find_appimage_file(folder: str) -> str:
+    for r, d, files in os.walk(folder):
+        for f in files:
+            if f.lower().endswith('.appimage'):
+                return '{}/{}'.format(folder, f)