make sure we don't have namespace clashes between libraries and apps

* All loging prefixes in libraries should be DL like DLINP
* All signals / subsystems should be called S_L_* SS_L_*
* All command nodes should be called L_*_NODE

This makes sure existinc code still compiles as expected
diff --git a/include/osmocom/vty/command.h b/include/osmocom/vty/command.h
index 4104d76..a6c2c5c 100644
--- a/include/osmocom/vty/command.h
+++ b/include/osmocom/vty/command.h
@@ -74,8 +74,8 @@
 
 	VTY_NODE,		/* Vty node. */
 
-	E1INP_NODE,		/* E1 line in libosmo-abis. */
-	IPA_NODE,		/* IPA proxying commands in libosmo-abis. */
+	L_E1INP_NODE,		/* E1 line in libosmo-abis. */
+	L_IPA_NODE,		/* IPA proxying commands in libosmo-abis. */
 
 	_LAST_OSMOVTY_NODE
 };