seal: Rework contracts API (#6573)

* Transition getter functions to not use scratch buffer

* Remove scratch buffer from ext_get_storage

* Remove scratch buffer from ext_call

* Remove scratch buffer from ext_instantiate

* Add ext_input and remove scratch buffer

* Rework error handling (changes RPC exposed data)

* ext_return passes a flags field instead of a return code
	* Flags is only for seal and not for the caller
	* flags: u32 replaced status_code: u8 in RPC exposed type
* API functions use a unified error type (ReturnCode)
* ext_transfer now traps on error to be consistent with call and instantiate

* Remove the no longer used `Dispatched` event

* Updated inline documentation

* Prevent skipping of copying the output for getter API

* Return gas_consumed from the RPC contracts call interface

* Updated COMPLEXTITY.md

* Rename ext_gas_price to ext_weight_to_fee

* Align comments with spaces

* Removed no longer used `ExecError`

* Remove possible panic in `from_typed_value`

* Use a struct as associated data for SpecialTrap::Return

* Fix nits in COMPLEXITY.md

* Renamed SpecialTrap to TrapReason

* Fix test

* Finish renaming special_trap -> trap_reason

* Remove no longer used get_runtime_storage

* fixup! Remove no longer used get_runtime_storage

* Removed tabs for comment aligment

substrate/bin/node/runtime/src/lib.rs

@@ -1066,12 +1066,13 @@ impl_runtime_apis! {
 			gas_limit: u64,
 			input_data: Vec<u8>,
 		) -> ContractExecResult {
-			let exec_result =
+			let (exec_result, gas_consumed) =
 				Contracts::bare_call(origin, dest.into(), value, gas_limit, input_data);
 			match exec_result {
 				Ok(v) => ContractExecResult::Success {
-					status: v.status,
+					flags: v.flags.bits(),
 					data: v.data,
+					gas_consumed: gas_consumed,
 				},
 				Err(_) => ContractExecResult::Error,
 			}