Reorganize repo: move scripts to contrib/scripts/, clean up .gitignore, untrack backup files

contrib/scripts/listassetchainparams

@@ -0,0 +1,24 @@
+#!/usr/bin/env python2
+import os
+import json
+
+def format_param(param, value):
+    return '-' + param + '=' + value
+
+script_dir = os.path.dirname(os.path.abspath(__file__))
+# Look for assetchains.json in same dir first, then in src/
+json_path = os.path.join(script_dir, 'assetchains.json')
+if not os.path.exists(json_path):
+    json_path = os.path.join(script_dir, '..', '..', 'src', 'assetchains.json')
+with open(json_path) as file:
+    assetchains = json.load(file)
+
+for chain in assetchains:
+    params = []
+    for param, value in chain.items():
+        if isinstance(value, list):
+            for dupe_value in value:
+                params.append(format_param(param, dupe_value))
+        else:
+            params.append(format_param(param, value))
+    print(' '.join(params))