Introduce the wasmtime-explorer crate (#5975)

This implements Godbolt Compiler Explorer-like functionality for Wasmtime and
Cranelift. Given a Wasm module, it compiles the module to native code and then
writes a standalone HTML file that gives a split pane view between the WAT and
ASM disassemblies.

crates/explorer/src/.eslintrc.yml

@@ -0,0 +1,8 @@
+root: true
+
+env:
+  browser: true
+  es2022: true
+
+extends:
+  - "eslint:recommended"