Updated AppData file, closes #5117

- Renamed AppData file to use reverse-DNG scheme.
- Updated id to use reverse-DNG scheme.
- Added launchable-type.
- Added releases.
- Add provides.

com.rawtherapee.RawTherapee.appdata.xml

@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <component type="desktop">
-    <id>rawtherapee.desktop</id>
+    <id>com.rawtherapee.RawTherapee.desktop</id>
     <name>RawTherapee</name>
     <summary>An advanced raw photo development program</summary>
     <summary xml:lang="cs">Program pro konverzi a zpracování digitálních raw fotografií</summary>
@@ -33,6 +33,14 @@
     <url type="help">http://rawpedia.rawtherapee.com/</url>
     <url type="homepage">http://rawtherapee.com/</url>
     <url type="translate">https://discuss.pixls.us/t/localization-how-to-translate-rawtherapee-and-rawpedia/2594</url>
+    <launchable type="desktop-id">com.rawtherapee.RawTherapee.desktop</launchable>
+    <releases>
+        <release version="5.5" date="2018-12-17" type="stable"></release>
+    </releases>
+    <provides>
+        <binary>rawtherapee</binary>
+        <binary>rawtherapee-cli</binary>
+    </provides>
     <screenshots>
         <screenshot type="default">
             <caption>HDR DNG of a misty morning in the countryside</caption>