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
```

src/commands/config.rs

@@ -17,7 +17,7 @@ pub enum ConfigCommand {
 
 impl ConfigCommand {
     /// Executes the command.
-    pub fn execute(&self) -> Result<()> {
+    pub fn execute(self) -> Result<()> {
         match self {
             Self::New(c) => c.execute(),
         }
@@ -35,7 +35,7 @@ pub struct ConfigNewCommand {
 
 impl ConfigNewCommand {
     /// Executes the command.
-    pub fn execute(&self) -> Result<()> {
+    pub fn execute(self) -> Result<()> {
         let path = wasmtime_cache::create_new_config(self.path.as_ref())?;
 
         println!(