Code review feedback changes.

* Add `anyhow` dependency to `wasmtime-runtime`.
* Revert `get_data` back to `fn`.
* Remove `DataInitializer` and box the data in `Module` translation instead.
* Improve comments on `MemoryInitialization`.
* Remove `MemoryInitialization::OutOfBounds` in favor of proper bulk memory
  semantics.
* Use segmented memory initialization except for when the uffd feature is
  enabled on Linux.
* Validate modules with the allocator after translation.
* Updated various functions in the runtime to return `anyhow::Result`.
* Use a slice when copying pages instead of `ptr::copy_nonoverlapping`.
* Remove unnecessary casts in `OnDemandAllocator::deallocate`.
* Better document the `uffd` feature.
* Use WebAssembly page-sized pages in the paged initialization.
* Remove the stack pool from the uffd handler and simply protect just the guard
  pages.

tests/all/pooling_allocator.rs

@@ -48,7 +48,10 @@ fn memory_limit() -> Result<()> {
     // Module should fail to validate because the minimum is greater than the configured limit
     match Module::new(&engine, r#"(module (memory 4))"#) {
         Ok(_) => panic!("module compilation should fail"),
-        Err(e) => assert_eq!(e.to_string(), "Validation error: memory index 0 has a minimum page size of 4 which exceeds the limit of 3")
+        Err(e) => assert_eq!(
+            e.to_string(),
+            "memory index 0 has a minimum page size of 4 which exceeds the limit of 3"
+        ),
     }
 
     let module = Module::new(
@@ -243,7 +246,10 @@ fn table_limit() -> Result<()> {
     // Module should fail to validate because the minimum is greater than the configured limit
     match Module::new(&engine, r#"(module (table 31 funcref))"#) {
         Ok(_) => panic!("module compilation should fail"),
-        Err(e) => assert_eq!(e.to_string(), "Validation error: table index 0 has a minimum element size of 31 which exceeds the limit of 10")
+        Err(e) => assert_eq!(
+            e.to_string(),
+            "table index 0 has a minimum element size of 31 which exceeds the limit of 10"
+        ),
     }
 
     let module = Module::new(