Updated RuboCop to the latest version

Updated RuboCop configuration according to recommended settings.
Updated RuboCop TODO file.

Bug: 117989
Change-Id: If934078beabc5498f929bbd7a26689dbd2ab7810

.rubocop.yml

@@ -1 +1,23 @@
 inherit_from: .rubocop_todo.yml
+
+AllCops:
+  StyleGuideCopsOnly: true
+
+# Uncomment when the repository is cleaned up
+# Metrics/LineLength:
+#   Max: 100
+
+Metrics/MethodLength:
+  Enabled: false
+
+Style/Alias:
+  Enabled: false
+
+Style/SignalException:
+  Enabled: false
+
+Style/StringLiterals:
+  EnforcedStyle: single_quotes
+
+Style/TrivialAccessors:
+  ExactNameMatch: true