[#234] Refactor OBS

[alvyn279]

• Migrate globals from component state variables to redux variables
• Partition render() into multiple functions
• Clean up date-utils functions
• Remove redundant functions
• Rename functions
• Fix tests

before:

interface Props extends WithStyles<typeof styles>, WithSnackbarProps{
    orderDetails: OrderDetails,
    showOrderInfoDrawer: boolean,
    onTimestampSelected: Function,
    currentOrderbookTimestamp: string,
    lastModificationType: LastModificationType,
}

interface State {
    lastSodOffset: bigInt.BigInteger,
    selectedDateNano: bigInt.BigInteger,
    selectedTimeString: string,
    datePickerValue: moment.Moment | null,
    selectedInstrument: string,
    instruments: Array<string>,
    listItems: ListItems,
    maxQuantity: number,
    topOfBookItems: Array<TopOfBookItem>,
    loadingInstruments: boolean,
    loadingOrderbook: boolean,
    loadingGraph: boolean,
    graphUnavailable: boolean,
    graphStartTime: bigInt.BigInteger,
    graphEndTime: bigInt.BigInteger,
    playback: boolean,
}

after:

interface Props extends WithStyles<typeof styles>, WithSnackbarProps {
    orderDetails: OrderDetails,
    showOrderInfoDrawer: boolean,
    onTimestampSelected: Function,
    currentOrderbookTimestamp: string,
    lastModificationType: LastModificationType,
    timeString: string,
    selectedDateNano: bigInt.BigInteger,
    onPlayback: Function,
    playback: boolean,
    instruments: Array<string>,
}

interface State {
    lastSodOffset: bigInt.BigInteger,
    datePickerValue: moment.Moment | null,
    selectedInstrument: string,
    listItems: ListItems,
    maxQuantity: number,
    topOfBookItems: Array<TopOfBookItem>,
    loadingOrderbook: boolean,
    loadingGraph: boolean,
    graphUnavailable: boolean,
    clickedGraph: boolean,
}