use types v6

[shunjizhan]

Change

• upgraded to use new acala types v6, and updated polkadot api to latest version
• removed temp runtime type patch, they are now all available in the acala types
• removed legacy createApi file

fix #578
fix #766

Test

• all tests still pass
• manually inspected that every api.xxx has a precise TS signature
• all methods are now decorated, so starting rpc adapter with latest runtime 2200 doesn't throw any of the previous warnings

API/INIT: RPC methods not decorated: chainHead_unstable_body, chainHead_unstable_call, chainHead_unstable_follow, chainHead_unstable_genesisHash, chainHead_unstable_header, chainHead_unstable_stopBody, chainHead_unstable_stopCall, chainHead_unstable_stopStorage, chainHead_unstable_storage, chainHead_unstable_unfollow, chainHead_unstable_unpin, transaction_unstable_submitAndWatch, transaction_unstable_unwatch
API/INIT: mandala/2200: Not decorating runtime apis without matching versions: Metadata/2 (1 known)