Maximum extrinsic weight limit (#6067)

* Only check single extrinsics weight limit in validate_transaction.

* Add missing parameter to all pallets.

* Add tests, fix default configuration.

* Bump spec version.

* Use AvailableBlockRation to calculate MaxExtrinsicWeight

Author: tomusdrw

src/mock.rs

@@ -79,6 +79,7 @@ impl frame_system::Trait for Test {
 	type DbWeight = ();
 	type BlockExecutionWeight = ();
 	type ExtrinsicBaseWeight = ();
+	type MaximumExtrinsicWeight = MaximumBlockWeight;
 	type MaximumBlockLength = MaximumBlockLength;
 	type AvailableBlockRatio = AvailableBlockRatio;
 	type Version = ();