[fastx dist sys] Design and implement bridge logic + Light Clients

[gdanezis]

fastx should interop with other important chains, such as ETH or Solana. For this we need to implement 2-way bridges that allow:

• Assets issued on another chain to be imported to fastx, and eventually re-exported to a new owner on the other chain.
• Assets issued on fastx to be exported to another chain and eventually re-imported to fastx.

We also would like to support light client reads onto the fastx state, which would allow trustless third party services that provide APIs for read.

Currently our thinking is to use the committee of fastx to authorise these actions through a collective signature, but other options are welcome.

[levicook]

Has there been progress on implementing a light client?