feat(web): add initial webui and README with demos

Add webui package with first demo for the WASM-UTXO package. The webui
provides a simple, framework-free demo environment to showcase
functionality of the BitGoWASM packages.

- Create README explaining the project structure
- Add address converter demo for wasm-utxo
- Use a clean, monospace-oriented design
- Remove old implementation files
- Implement simple router for multi-page support

Issue: BTC-0

Co-authored-by: llm-git <llm-git@ttll.de>

Author: OttoAllmendinger

package-lock.json

@@ -0,0 +1,10 @@
+# BitGoWASM WebUI
+
+This project contains demos for the different wasm packages in the BitGoWASM project.
+
+## Architecture
+
+- No frontend frameworks
+- Demo vibe for UI: monospace font
+- Demo of the `@bitgo/wasm-utxo` package lives in src/wasm-utxo
+- Toplevel index.html contains navigation to the sub-package demo sites