Add a Readme.md file for the MCP protocol. (#565)
Add a Readme.md file for the MCP protocol. (#565)

* Add a Readme.md file for the MCP protocol.

* Add a link to the XDS protocol.

geeknoid/api,istio/api,geeknoid/api,rshriram/api,rshriram/api,istio/api,geeknoid/api,geeknoid/api,istio/api,istio/api,rshriram/api