Add description of needed APIs on operator.md

[nrooney]

I remember we spoke about these but I can't seem to verbalise them in the right way - can you give it a shot? It's this bit:

Three APIs will be needed:

• Web apis - PLEASE ADD
• Device api - PLEASE ADD
• Carrier api - PLEASE ADD

[kevinprince]

Have started adding pieces to branch 9_api_descriptions

https://github.com/Data-Info-API/Architecture/compare/9_api_descriptions