gnss-mgr: Add example config file

The default config file has been emptied to not set dummy values
A example file has been added so the user knows which fields can be set.

BugzID: 65564

recipes-connectivity/gnss-mgr/gnss-mgr.bb

@@ -30,7 +30,7 @@ S = "${WORKDIR}/git"
 
 do_install_append() {
     install -d ${D}${sysconfdir}/gnss
-    install -m 0644 ${S}/config/gnss-neom8.conf ${D}${sysconfdir}/gnss/
+    install -m 0644 ${S}/config/* ${D}${sysconfdir}/gnss/
 
     install -d ${D}/${systemd_unitdir}/system/
     install -m 0644 ${S}/systemd/gnss-mgr.service ${D}/${systemd_unitdir}/system/