Add API gateway logging (#189)

Author: adamtry

DocumentsApi/serverless.yml

@@ -9,6 +9,12 @@ provider:
   tracing:
     apiGateway: true
     lambda: true
+  logs:
+    restApi:
+      accessLogging: true
+      executionLogging: true
+      fullExecutionData: true
+      level: INFO
   environment:
     CONNECTION_STRING: Host=${ssm:/documents-api/${self:provider.stage}/postgres-hostname};Port=${ssm:/documents-api/${self:provider.stage}/postgres-port};Database=${ssm:/documents-api/${self:provider.stage}/postgres-database};Username=${ssm:/documents-api/${self:provider.stage}/postgres-username};Password=${ssm:/documents-api/${self:provider.stage}/postgres-password}
     BUCKET_NAME: document-evidence-store-${self:provider.stage}-bucket