make it possible to get > 365 days of historical schedule data

[kylematoba]

No description provided.

[gnzsnz]

@kylematoba may i ask you to elaborate the motivation behind your PR.

this will break existing code.

[pavel-slama]

@kylematoba How about to:

• keep both arguments - numDays and bar_size with default None values
• issue DeprecationWarning when the numDays is used (not None) so that users are warned but existing code keeps working
• add some default value when both are None
• convert numDays into bar_size in both reqHistoricalSchedule and reqHistoricalScheduleAsync
• reqHistoricalScheduleGeneral could be removed

Also seems like the project is using camelCase, so maybe follow that with barSize instead of bar_size.