bird: initial creation (#9928)

Signed-off-by: Marek Küthe <m.k@mk16.de>

pages/common/bird.md

@@ -0,0 +1,13 @@
+# bird
+
+> BIRD Internet Routing Daemon.
+> Routing daemon with support for BGP, OSPF, Babel and others.
+> More information: <https://bird.network.cz/>.
+
+- Start Bird with a specific configuration file:
+
+`bird -c {{path/to/bird.conf}}`
+
+- Start Bird as a specific user and group:
+
+`bird -u {{username}} -g {{group}}`