add AppStream metadata

Change-Id: Ib8108f5b6182b0a973ad73fb7b50262d4bbe6a38

jami-daemon.metainfo.xml

+<?xml version="1.0" encoding="UTF-8"?>
+<!-- Copyright 2018 Savoir-faire Linux -->
+<component>
+ <id>net.jami.daemon</id>
+ <metadata_license>CC-BY-SA-3.0</metadata_license>
+ <project_license>GPL-3.0+</project_license>
+ <name>Jami daemon</name>
+ <summary>Jami is a software for secure communications with distributed architecture</summary>
+
+ <description>
+  <p>
+   Jami is a free and open source software, which allows to make encrypted audio or video calls and to send files and messages around the world. Jami is an official GNU package, that uses fully distributed architecture and independent from any centralized service. Additional support for SIP communications is provided.
+  </p>
+  <p>
+   Features:
+   <ul>
+   <li>Audio and video calls, instant messaging, file transfers</li>
+   <li>Distributed architecture — p2p connections, DHT for a peer discovery</li>
+   <li>Multi-device support</li>
+   <li>Available on Windows, MacOS, iOS, GNU/Linux, Android and Android TV</li>
+   </ul>
+  </p>
+ </description>
+
+ <url type="homepage">https://jami.net/</url>
+ <url type="bugtracker">https://git.jami.net/savoirfairelinux/ring-daemon/issues/</url>
+
+ <provides>
+  <dbus type="user">cx.ring.Ring</dbus>
+​ </provides>
+
+ <categories>
+  <category>Network</category>
+  <category>P2P</category>
+  <category>InstantMessaging</category>
+  <category>FileTransfer</category>
+ </categories>
+
+ <content_rating type="oars-1.1">
+  <content_attribute id="social-chat">intense</content_attribute>
+  <content_attribute id="social-audio">intense</content_attribute>
+ </content_rating>
+
+</component>