gitignore Python bytecode - the new gate test writes controller/scripts/__pycache__

test_golden_notice.py imports controller_gates.py to assert the golden-notice is registered
non-blocking, which makes CPython write bytecode beside the scripts. felhom.eu already ignored it;
this repo did not, so it would have reappeared on every test run and been one careless 'git add'
away from being committed.

.gitignore

@@ -0,0 +1,5 @@
+
+# Python bytecode from the gate scripts and their tests (R-404 added test_golden_notice.py,
+# which imports controller_gates.py and so writes controller/scripts/__pycache__).
+__pycache__/
+*.pyc