multi: move itest out of lntest

This commit moves all the test cases living in `itest` out of `lntest`,
further making `lntest` an independent package for general testing.

itest/log_check_errors.sh

@@ -0,0 +1,26 @@
+#!/bin/bash
+
+BASEDIR=$(dirname "$0")
+
+echo ""
+
+# Filter all log files for errors, substitute variable data and match against whitelist.
+find $BASEDIR -name "*.log" | xargs grep -h "\[ERR\]" | \
+sed -r -f $BASEDIR/log_substitutions.txt | \
+sort | uniq | \
+grep -Fvi -f $BASEDIR/log_error_whitelist.txt
+
+# If something shows up (not on whitelist) exit with error code 1.
+if [[ $? -eq 0 ]]; then
+        echo ""
+        echo "In the itest logs, the log line (patterns) above were detected."
+        echo "[ERR] lines are generally reserved for internal errors."
+        echo "Resolve the issue by either changing the log level or adding an "
+        echo "exception to log_error_whitelist.txt"
+        echo ""
+
+        exit 1
+fi
+
+echo "No itest errors detected."
+echo ""