Add script that updates remote UI.

This script makes it easy to update the web page at
https://google.github.io/filament/remote/ even if you do not have the
emscripten SDK. It works by downloadinug the latest continuous web
build, then placing the wasm file in the right place.

After running the script, the user must make a git commit to finish the
operation.

docs/remote/update.sh

@@ -0,0 +1,17 @@
+#!/bin/bash
+
+pushd "$(dirname "$0")" > /dev/null
+
+curl -OL https://nightly.link/google/filament/workflows/web-continuous/main/filament-web.zip
+unzip -q filament-web.zip
+tar -xvzf filament-release-web.tgz
+rm filament-release-web.tgz
+rm filament-web.zip
+rm filament.d.ts
+cp ../../web/samples/remote.html index.html
+
+popd
+
+git status
+echo ""
+echo "All done! Next, make a git commit that updates docs/remote."