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/environ/src/data_structures.rs

@@ -10,7 +10,9 @@ pub mod ir {
 }
 
 pub mod settings {
-    pub use cranelift_codegen::settings::{builder, Builder, Configurable, Flags, SetError};
+    pub use cranelift_codegen::settings::{
+        builder, Builder, Configurable, Flags, OptLevel, SetError,
+    };
 }
 
 pub mod isa {

crates/environ/src/tunables.rs

@@ -1,5 +1,7 @@
+use serde::{Deserialize, Serialize};
+
 /// Tunable parameters for WebAssembly compilation.
-#[derive(Clone, Hash)]
+#[derive(Clone, Hash, Serialize, Deserialize)]
 pub struct Tunables {
     /// For static heaps, the size in wasm pages of the heap protected by bounds checking.
     pub static_memory_bound: u32,