Cross-chain query spec draft (#735)

* first draft ibc queries

* minor fixes

* address Aditya minor comments

* fix typo

* fix typo

* address Chris comments

* address Carlos comments

* add clean query result function

* Rename spec/app/ics-interchain-queries/README.md to spec/app/ics-031-crosschain-queries/README.md

* minor change

* add relayer address to functions and localTimeoutTimestamp

* add paragraph addition state machine logic

* query results into private store

* minor change

* major changes to assumptions

* new motivation

* typo

* minor changes