Statemint Reserve Asset Transfer (#552)

* add AssetId type alias in statemint-common

* add FungiblesAdapter to allow for asset transactions via XCM

* use custom Polkadot

* fix FungiblesAdapter usage and add CheckingAccount

* update deps

* remove polkadot overrides

* update deps

* pull NonZeroIssuance struct into common + add FungiblesTransactor to Statemine and Westmint

* remove unnecessary tuple wrapping + adjust asset transactor comments

* accept statemint as reserve in rococo test parachain

* adjust parachain config (add Statemint as reserve)

* add test and docs for AssetsFrom

* cargo fmt

Co-authored-by: Ricardo Rius <ricardo@parity.io>
Co-authored-by: Shawn Tabrizi <shawntabrizi@gmail.com>

cumulus/Cargo.lock

@@ -6109,6 +6109,8 @@ dependencies = [
  "sp-runtime",
  "sp-std",
  "substrate-wasm-builder",
+ "xcm",
+ "xcm-executor",
 ]
 
 [[package]]
@@ -8367,6 +8369,7 @@ dependencies = [
  "pallet-transaction-payment-rpc-runtime-api",
  "pallet-xcm",
  "parachain-info",
+ "parachains-common",
  "parity-scale-codec",
  "polkadot-parachain",
  "scale-info",