Add first class support to token operations

[tomerweller]

as defined in the token interface https://soroban.stellar.org/docs/reference/interfaces/token-interface

[leighmcculloch]

We should approach implementing this by implementing client binding generation for Javascript in the soroban-cli:

• Contract Spec: Add CLI command that generates a TypeScript type from .wasm. stellar-cli#8

Once we have client binding generation this SDK can embed as a first-class feature the generated client binding for the token contract whose interface is exported in the soroban-token-spec crate.

[tomerweller]

the token related operations should also have an expected footprint that can be codified in the sdk, rather than going through preflight

[Shaptic]

I believe this is closed by the new TypeScript bindings.