Shuffle around the wiggle crates (#1414)

* Shuffle around the wiggle crates

This commit reorganizes the wiggle crates slightly by performing the
following transforms:

* The `crates/wiggle` crate, previously named `wiggle`, was moved to
  `crates/wiggle/crates/macro` and is renamed to `wiggle-macro`.

* The `crates/wiggle/crates/runtime` crate, previously named
  `wiggle-runtime`, was moved to `crates/wiggle` and is renamed to
  `wiggle`.

* The new `wiggle` crate depends on `wiggle-macro` and reexports the macro.

The goal here is that consumers only deal with the `wiggle` crate
itself. No more crates depend on `wiggle-runtime` and all dependencies
are entirely on just the `wiggle` crate.

* Remove the `crates/wiggle/crates` directory

Move everything into `crates/wiggle` directly, like `wasi-common`

* Add wiggle-macro to test-all script

* Fixup a test

crates/wiggle/generate/src/lib.rs

@@ -0,0 +1,59 @@
+pub mod config;
+mod funcs;
+mod lifetimes;
+mod module_trait;
+mod names;
+mod types;
+
+use proc_macro2::TokenStream;
+use quote::quote;
+
+pub use config::Config;
+pub use funcs::define_func;
+pub use module_trait::define_module_trait;
+pub use names::Names;
+pub use types::define_datatype;
+
+pub fn generate(doc: &witx::Document, config: &Config) -> TokenStream {
+    let names = Names::new(config); // TODO parse the names from the invocation of the macro, or from a file?
+
+    let types = doc.typenames().map(|t| define_datatype(&names, &t));
+
+    let modules = doc.modules().map(|module| {
+        let modname = names.module(&module.name);
+        let fs = module.funcs().map(|f| define_func(&names, &f));
+        let modtrait = define_module_trait(&names, &module);
+        let ctx_type = names.ctx_type();
+        quote!(
+            pub mod #modname {
+                use super::#ctx_type;
+                use super::types::*;
+                #(#fs)*
+
+                #modtrait
+            }
+        )
+    });
+
+    let metadata = if config.emit_metadata {
+        let doc_text = &format!("{}", doc);
+        quote! {
+            pub mod metadata {
+                pub const DOC_TEXT: &str = #doc_text;
+                pub fn document() -> wiggle::witx::Document {
+                    wiggle::witx::parse(DOC_TEXT).unwrap()
+                }
+            }
+        }
+    } else {
+        quote!()
+    };
+
+    quote!(
+        pub mod types {
+            #(#types)*
+        }
+        #(#modules)*
+        #metadata
+    )
+}