bankd: Add GSMTAP functionality for SIM traffic

If a --gsmtap-host (-g) address is specified on the command line, trace
SIM ATRs and APDUs to the given IP. If --gsmtap-slot (-G) is provided,
limit tracing to the specified bank slot number. This feature may be
useful when diagnosing issues with the remote SIM framework.

Added new log category: DGSMTAP

Also, cleaned up alignment in bankd --help output and removed unused -o option.

Change-Id: I05b599858d8758633aa56c3f12f258c27cf42d08
diff --git a/src/debug.c b/src/debug.c
index fb8bb4b..2f163d3 100644
--- a/src/debug.c
+++ b/src/debug.c
@@ -52,6 +52,11 @@
 		.loglevel = LOGL_INFO,
 		.enabled = 1,
 	},
+	[DGSMTAP] = {
+		.name = "DGSMTAP",
+		.loglevel = LOGL_INFO,
+		.enabled = 1,
+	},
 };
 
 const struct log_info log_info = {