Add AppStream metadata

- Added metainfo.xml file following AppStream specification

- Extracted metadata from debian/control

- Included project URLs and developer information

- Added proper categorization and content rating

Co-Authored-By: Warp <agent@warp.dev>

Author: Vitexus

debian/io.github.spoje_net.cnb_cache.metainfo.xml

@@ -13,8 +13,8 @@
   <categories>
     <category>Utility</category>
   </categories>
-  <url type="homepage">https://github.com/Spoje-NET/CNB-Cache</url>
-  <url type="bugtracker">https://github.com/Spoje-NET/CNB-Cache/issues</url>
+  <url type="homepage">https://github.com/Spoje-NET/CNB-Tools</url>
+  <url type="bugtracker">https://github.com/Spoje-NET/CNB-Tools/issues</url>
   <developer id="io.github.spoje_net">
     <name>Spoje.Net</name>
   </developer>