command.wasm : add voice assistant example for the Web (#171)

Same as the command-line tool "command", but runs in the browser

Also, added helper script "extra/deploy-wasm.sh" and fixed some timing
constants for the WASM examples.

examples/command.wasm/README.md

@@ -0,0 +1,23 @@
+# command.wasm
+
+This is a basic Voice Assistant example that accepts voice commands from the microphone.
+It runs in fully in the browser via WebAseembly.
+
+Online demo: https://whisper.ggerganov.com/command/
+
+Terminal version: https://github.com/ggerganov/whisper.cpp/examples/command
+
+## Build instructions
+
+```bash
+# build using Emscripten (v3.1.2)
+git clone https://github.com/ggerganov/whisper.cpp
+cd whisper.cpp
+mkdir build-em && cd build-em
+emcmake cmake ..
+make -j
+
+# copy the produced page to your HTTP path
+cp bin/command.wasm/*       /path/to/html/
+cp bin/libcommand.worker.js /path/to/html/
+```