Small Yellow improvements (#1875)

* Enable additional LED triggers

* Improve Yellow device tree

Fix soundcard name and use BTN_1 as key code.

* Add input-event-daemon configuration

Add minimal input-event-daemon configuration to avoid the default
configuration taking effect. This minimal configuration triggers
the USB configuration import on button press.

buildroot-external/rootfs-overlay/etc/input-event-daemon.conf

@@ -0,0 +1,10 @@
+#
+# /etc/input-event-daemon.conf
+#
+
+[Global]
+listen = /dev/input/by-path/platform-gpio-keys-event
+
+[Keys]
+BTN_1     = /usr/bin/systemctl start hassos-config.service
+