Add --wait and --timeout flags to wamer publish

[ayys]

The --wait flag

Rationale: When a large package is published, the user has to wait for a while to
be able to use it. This is because the webc of the package is not available on
the registry until the package is fully processed.

The registry now supports passing a wait flag to the publish query. This will
cause the query to wait until the webc of the package is available on the
registry before exiting. By default, this is set to false (for backwards
compatibility), and the --wait flag on the CLI enables it.

The --timeout flag

Rationale: When publishing a large package with the --wait flag - it may take a long
time.

The --timeout flag can be used to set the timeout for http requests made while
publishing the package. This is important because processing large webc files
may take a while. The default timeout is set to 30 seconds, but can be increased
if necessary (e.g. when publishing large packages).

Example usage:

wasmer publish --wait --timeout 120s && wasmer run <package-name>

Since the package is immediately available, the above command is possible.

[Michael-F-Bryan]

Looks like a mostly straightforward addition.

I've added some comments for how we could make the --timeout argument more user-friendly (i.e. let them do --timeout=60s), but don't see any issues.

Thanks for cleaning up the wasmer-registry code, by the way!