Add synapse role

For all the hipster kids.

roles/synapse/templates/log.config.j2

@@ -0,0 +1,37 @@
+# [2]: https://matrix-org.github.io/synapse/latest/structured_logging.html
+
+version: 1
+formatters:
+    precise:
+        format: '%(asctime)s - %(name)s - %(lineno)d - %(levelname)s - %(request)s - %(message)s'
+
+handlers:
+    file:
+        class: logging.handlers.TimedRotatingFileHandler
+        formatter: precise
+        filename: /var/lib/synapse/{{ password.server_name }}.log
+        when: midnight
+        backupCount: 3  # Does not include the current log file.
+        encoding: utf8
+
+    buffer:
+        class: synapse.logging.handlers.PeriodicallyFlushingMemoryHandler
+        target: file
+
+        capacity: 10
+        flushLevel: 30  # Flush immediately for WARNING logs and higher
+        period: 5
+
+    console:
+        class: logging.StreamHandler
+        formatter: precise
+
+loggers:
+    synapse.storage.SQL:
+        level: INFO
+
+root:
+    level: INFO
+    handlers: [buffer]
+
+disable_existing_loggers: false