* convert local AssetNotFound errors into XcmError::AssetNotFound
aims allow the tuple implementation of TransactAsset to iterate properly
* add more XcmError descriptions
* adjust the rest of the TransactAsset tuple implementation to the behavior of can_check_in
* fix copy paste errors
* keep iterating tuple on Unimplemented error in TransactAsset
* add tests for tuple implementation of TransactAsset
* Update xcm/src/v0/traits.rs
Co-authored-by: Andronik Ordian <write@reusable.software>
Co-authored-by: Shawn Tabrizi <shawntabrizi@gmail.com>
Co-authored-by: Andronik Ordian <write@reusable.software>