Add a `forc call` command for calling contract methods

Currently, `forc-client` provides basic support for:

- deploying contracts (`forc deploy`) and
- running scripts (`forc run`)

However, there's no way to **call** a deployed contract's ABI method (other than indirectly via a script with `forc run`).

This could be useful e.g. for testing locally deployed contracts from the command line.

## Rough thoughts

An invocation might look something like:

```console
forc call --contract-abi "out/debug/my-contract-abi.json" --contract-id "..." --method-id "..." arg1 arg2 arg3
```

- I'm not 100% sure how we determine the method ID just yet (or if that's how we want to refer to methods).
- I imagine we'll need to know about the contract's ABI.
- W.r.t. handling arguments, we could consider following suit with FuelLabs/forc#196.