Add a compile command to Wasmtime.

This commit adds a `compile` command to the Wasmtime CLI.

The command can be used to Ahead-Of-Time (AOT) compile WebAssembly modules.

With the `all-arch` feature enabled, AOT compilation can be performed for
non-native architectures (i.e. cross-compilation).

The `Module::compile` method has been added to perform AOT compilation.

A few of the CLI flags relating to "on by default" Wasm features have been
changed to be "--disable-XYZ" flags.

A simple example of using the `wasmtime compile` command:

```text
$ wasmtime compile input.wasm
$ wasmtime input.cwasm
```

crates/jit/Cargo.toml

@@ -46,6 +46,7 @@ lightbeam = ["wasmtime-lightbeam"]
 jitdump = ["wasmtime-profiling/jitdump"]
 vtune = ["wasmtime-profiling/vtune"]
 parallel-compilation = ["rayon"]
+all-arch = ["cranelift-codegen/all-arch"]
 
 # Try the experimental, work-in-progress new x86_64 backend. This is not stable
 # as of June 2020.