Write proxy-wasm envoy / gateway UOR mutation webhook

[usrbinkat]

Build a wasm app to enable low overhead UOR query on legacy apps.

Criteria:

• [ ] Written in Go
• [ ] Compile to Wasm
• [ ] Run in a gateway (one example)
• [ ] Act based on UOR packet header
• [ ] Accept uri parameters for attribute query
• [ ] Return payload objects in response
• [ ] Demonstrate end result with a working static site