Use cargo publish --workspace instead of a custom publish script

#### Feature

See title

#### Benefit

This would allow getting rid of https://github.com/bytecodealliance/wasmtime/blob/main/scripts/publish.rs and in particular having to explicitly specify which packages to publish and in what order. It should also make publishing faster by publishing multiple crates at once and only waiting for the publish to be propagated when publishing a crate that has a just published crate as dependency.

#### Implementation

TODO: Do you have an implementation plan, and/or ideas for data structures or
algorithms to use?

#### Alternatives

TODO: What are the alternative implementation approaches or alternative ways to
solve the problem that this feature would solve? How do these alternatives
compare to this proposal?