distro: Add Salix (#679)

Author: gapan

data/distro.yml

@@ -594,3 +594,10 @@
     <p>You can use the Software app or browse <a href="https://flathub.org/">Flathub</a> to install some apps.</p>
     <p>If for some reason Flathub is not available, you can configure it manually using the following command:</p>
     <terminal-command>host-shell flatpak remote-add --user --if-not-exists flathub https://dl.flathub.org/repo/flathub.flatpakrepo</terminal-command>
+
+- name: Salix
+  logo: "salix.svg"
+  introduction: >
+    <h2>Flatpak is installed by default on Salix since version 15.0—no setup required!</h2>
+    <p>Flatpak comes preconfigured with the Flathub repository and desktop integration tools are included to allow 1-click install from Flathub.</p>
+    <p>All you have to do is <a href="https://flathub.org/">install some apps</a>!</p>