web-wasm,web-wasi: Add build tools

- Binaryen
- wabt
- WASI runtimes: wasmtime, wasmer, wavm, wasm3

imagefiles/wasmer-pwd.sh

@@ -0,0 +1,4 @@
+#!/usr/bin/env bash
+
+# Mount the PWD to enable access in try_run commands
+exec ${WASMER_DIR}/bin/wasmer run --dir=. --dir=$PWD "$@"

imagefiles/wasmtime-pwd.sh

@@ -0,0 +1,4 @@
+#!/usr/bin/env bash
+
+# Mount the PWD to enable access in try_run commands
+exec ${WASMTIME_HOME}/bin/wasmtime run --dir=. --dir=$PWD "$@"