WIP: data: Remove GNOME branding

This MR is part of an [initiative](GNOME/Initiatives#35) to fade out legacy app branding. Following the [Software Policy](https://wiki.gnome.org/Foundation/SoftwarePolicy), GNOME branding is reserved for official GNOME software (Core apps and Development tools.) You can find a summary in [this blog post](https://blogs.gnome.org/sophieh/2022/06/08/apps-attempt-of-a-status-report/).

If you think that your app is a special case that needs an exception from the software policy, we would ask you to leave a comment about your app's case in GNOME/Initiatives#35.

/label ~"9. Initiative: Legacy app branding"

data/org.gnome.meld.appdata.xml.in.in

@@ -48,7 +48,7 @@
   <url type="translate">https://wiki.gnome.org/TranslationProject</url>
   <update_contact>[email protected]</update_contact>
   <project_group>GNOME</project_group>
-  <developer_name>The GNOME Project</developer_name>
+  <developer_name>Kai Willadsen</developer_name>
   <translation type="gettext">meld</translation>
   <content_rating type="oars-1.1" />
   <releases>

meld.doap

@@ -18,7 +18,6 @@
   <developer-forum rdf:resource="https://discourse.gnome.org/tag/meld" />
   <download-page rdf:resource="https://download.gnome.org/sources/meld/" />
   <bug-database rdf:resource="https://gitlab.gnome.org/GNOME/meld/issues" />
-  <category rdf:resource="http://api.gnome.org/doap-extensions#apps" />
   <programming-language>Python</programming-language>
 
   <maintainer>