feat: add async XCM contract call scenario

[ashutoshvarma]

Pull Request Summary
Add Async XCM contract call experimental scenario to xcm-simulator tests.

NOTE
Based on #939

This PR adds,

• ink! contract PoC for async call to be used as fixture in tests
• xcm simulator scenarios performing async xcm calls from above contract.

Async XCM Contract Call

• Contract on ParaA will send below XCM to ParaB using call_runtime to perform some operation (like Transact).
• If Error, a Transact instr will be used to send an XCM back to ParaA which will call ERROR contract method.
• If Success, same as above but call SUCCESS method.

Xcm(vec![
	WithdrawAsset(..)
	BuyExecution(..)
	SetAppendix(Xcm(vec![
		Transcat { /* pallet_xcm::send() runtime call to call SUCCESS contract method in ParaA */ }
	]))
	SetErrorHandler(Xcm(vec![
		Transcat { /* pallet_xcm::send() runtime call to call ERROR contract method in ParaA */ }
	]))
	...
])

Check list

• added or updated unit tests
• updated Astar official documentation
• added OnRuntimeUpgrade hook for precompile revert code registration
• updated spec version
• updated semver

[shaunxw]

Some nitpicks. Not a pallet-contract expert so I basically skipped the contract impl part.

[Dinonard]

This adds the test - which is good!

Question - how will the non-runtime devs, or to be more precise, how will the smart contract devs know about this feature?

[ashutoshvarma]

@Dinonard I'm not sure why smart contract dev needs to know about this feature 🤔 , since this is for Runtime tests fixtures but I understand this needs to be put somewhere so that even runtime devs know about this.
I've added a small section in readme for this - af03b05.

EDIT: Sorry I miss understood, I thought you meant the build script.
I'm not sure we should advertise this since it is experimental and should not be used in production (not sure if can be used in production due to SafeCallFilter in other chains).
We can add a section in docs for this and with appropriate warning like

• use upgradeable contracts (in case Call changed)
• implement your own replay protection in smart contract

[github-actions]

Package	Line Rate	Branch Rate	Health
pallets/contracts-migration/src	0%	0%	❌
precompiles/sr25519/src	79%	0%	➖
chain-extensions/types/assets/src	0%	0%	❌
pallets/block-reward/src	85%	0%	✔
chain-extensions/xvm/src	0%	0%	❌
pallets/pallet-xvm/src/pallet	8%	0%	❌
precompiles/substrate-ecdsa/src	78%	0%	➖
pallets/custom-signatures/src	52%	0%	➖
precompiles/assets-erc20/src	76%	0%	➖
precompiles/utils/src	69%	0%	➖
chain-extensions/types/dapps-staking/src	0%	0%	❌
precompiles/xvm/src	61%	0%	➖
primitives/src	70%	0%	➖
primitives/src/xcm	70%	0%	➖
precompiles/xcm/src	85%	0%	✔
precompiles/dapps-staking/src	93%	0%	✔
pallets/pallet-xcm/src	54%	0%	➖
pallets/collator-selection/src	70%	0%	➖
chain-extensions/dapps-staking/src	0%	0%	❌
chain-extensions/types/xvm/src	0%	0%	❌
precompiles/utils/macro/src	0%	0%	❌
pallets/xc-asset-config/src	54%	0%	➖
chain-extensions/pallet-assets/src	0%	0%	❌
pallets/pallet-xvm/src	5%	0%	❌
pallets/dapps-staking/src	82%	0%	✔
pallets/dapps-staking/src/pallet	87%	0%	✔
Summary	55% (2196 / 3996)	0% (0 / 0)	➖

Minimum allowed line rate is 50%

[shaunxw]

LGTM