feat: add xcm transacting support

[mattsse]

Changes

• Adds support for dispatching pallet_proxy and pallet_staking calls on different chains
• Since the various parachains may use types other than configured for PINT, it is necessary to encode the calls depending on their destination
• Therefor the EncodeWith trait was introduced which is intended as wrapper around code::Encode but with an additional context provided (AssetId or Location) to encode the type properly
• Each pallet (staking, proxy) require their own Encoder type inside the remote asset manager, they ensure that the calls are encoded correctly and will be configured in the runtime.

Builds on #79

Tests

cargo test

Issues

• Closes Add support for transacting pallet_proxy calls #98

[clearloop]

Is there any reference for XCM calls? The structure here seems like a pallet?

[clearloop]

Rename remote-asset-manager/src/calls.rs to remote-asset-manager/src/calls/mod.rs?

Or move the calls to /root/primitives/xcm-calls ?

[mattsse]

Is there any reference for XCM calls? The structure here seems like a pallet?

Here are the expanded versions of the staking pallet
pallet-staking-expanded.rs.txt

and the polkadot runtime
polkadot-expanded.rs.txt

[mattsse]

Rename remote-asset-manager/src/calls.rs to remote-asset-manager/src/calls/mod.rs?

Or move the calls to /root/primitives/xcm-calls ?

I like the idea of moving this to primitives!

[clearloop]

Is there any reference for XCM calls? The structure here seems like a pallet?

Here are the expanded versions of the staking pallet
pallet-staking-expanded.rs.txt

and the polkadot runtime
polkadot-expanded.rs.txt

Emmmm, this calls is from polkadot/runtime/polkadot/src/lib.rs.... amazming..

[mattsse]

The relevant decoding happens upon arrival XCM Transact here:

https://github.com/paritytech/polkadot/blob/master/xcm/xcm-executor/src/lib.rs#L172-L177

[clearloop]

Should we add links like

• https://github.com/paritytech/polkadot/blob/master/runtime/polkadot/src/lib.rs
• https://github.com/paritytech/polkadot/blob/master/xcm/xcm-executor/src/lib.rs#L172-L177

To this README so that we can trace the new updates easily from the upstream when we need to update this pallet?

[mattsse]

Good idea, will add links and will also reference them in the docs