Re-work logging and command-line argument parsing

[Michael-F-Bryan]

When discussing #3948, we decided that the wasmer command shouldn't show any log messages unless the user explicitly sets the $RUST_LOG environment variable. That way there's no chance that logging will mess up the output you might get from a program.

I've also re-worked the CLI parsing code to be vanilla clap rather than having a mix of manual argument parsing and two different clap parsers. This means we no longer need to update that big match statement every time a new command or alias is added, plus it makes the code a lot more readable.

Fixes #3948.

[theduke]

Nice.

Love getting rid of the command hacks!

[syrusakbary]

Looks good, but can we have a test testing that wasmer awasifile.wasm still works before merging? Thanks!

[Michael-F-Bryan]

@syrusakbary most of the wasmer run integration tests already check wasmer run whatever.wasm and wasmer whatever.wasm, so we should be all good on that front 👌

For example,

wasmer/tests/integration/cli/tests/run.rs

Lines 339 to 354 in 2b867fa

	// test with "wasmer qjs.wasm"
	Command::new(get_wasmer_path())
	.arg(temp_dir.path())
	.arg("--")
	.arg("--quit")
	.assert()
	.success();
	// test again with "wasmer run qjs.wasm"
	Command::new(get_wasmer_path())
	.arg("run")
	.arg(temp_dir.path())
	.arg("--")
	.arg("--quit")
	.assert()
	.success();