* Add estimated time to pending transactions
* add sytles for pending transactions component
* add media queries styling for pending transactions component
* fix lint errors, remove extra spaces
* refactor code to call `fetchBasicGasAndTimeEstimates` method once
* refactor code to call `getgetRenderableTimeEstimate` method once
* fix, correct export to use `transaction-time-remaining-component`
* fix indentation issues after running `yarn lint`
* newBigSigDig in gas-price-chart.utils supports strings
* Code cleanup
* Ensure fetchBasicGasAndTimeEstimates is only called from tx-list if there are pending-txs
* Move gas time estimate utilities into utility file
* Move getTxParams to transaction selector file
* Add feature flag for display of remaining transaction time in tx history list
* Fix circular dependency by removing unused import of transactionSelector in selectors.js
* Use correct feature flag property name transactionTime
* Ensure that tx list component correctly responds to turning tx time feature on
* Prevent precision errors in newBigSigDig
* Code clean up for pending transaction times
* Update transaction-time-remaining feature to count down seconds, countdown seconds and show '< 30'
* Code clean up for transaction-time-remaining feature
