task: Add a task to build everything in this layer

Add a task to build test everything that is in this layer.
diff --git a/recipes-telephony/tasks/task-telephony-all.bb b/recipes-telephony/tasks/task-telephony-all.bb
new file mode 100644
index 0000000..7ee97ff
--- /dev/null
+++ b/recipes-telephony/tasks/task-telephony-all.bb
@@ -0,0 +1,25 @@
+DESCRIPTION = "Task for the meta-telephony layer. This is to build everything"
+LICENSE = "MIT"
+LIC_FILES_CHKSUM = "file://${COREBASE}/LICENSE;md5=3f40d7994397109285ec7b81fdeb3b58 \
+                    file://${COREBASE}/meta/COPYING.MIT;md5=3da9cfbcb788c80a0384361b4de20420"
+ALLOW_EMPTY = "1"
+PR = "r1"
+
+DEPENDS = "\
+        libosmo-abis \
+        libosmo-sccp \
+        libosmocore \
+        openbsc \
+        task-osmocom \
+        openggsn \
+        misdn-utils \
+        dahdi-linux \
+        dahdi-tools \
+        lcr \
+        asterisk \
+        libgsm \
+        ortp \
+        libdbi \
+        libdbi-drivers \
+    "
+