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

substrate/frame/example/src/lib.rs

@@ -754,6 +754,7 @@ mod tests {
 		type DbWeight = ();
 		type BlockExecutionWeight = ();
 		type ExtrinsicBaseWeight = ();
+		type MaximumExtrinsicWeight = MaximumBlockWeight;
 		type MaximumBlockLength = MaximumBlockLength;
 		type AvailableBlockRatio = AvailableBlockRatio;
 		type Version = ();