Ability to set the date directly when calling the constructor and other minor improvements

[Sanshain]

• append selectedDate option field to CalendarOptions. Its afford to set current date inside Calendar constructor
• allow to hide selected date before user select date (now today is auto selecting)
• set month bounds via CalendarOptions

Example:

let date = new Date;
date.setDate(55)

const calendar = new Calendar({
    id: "#calendar",
    calendarSize: "small",
    currentDate: date,
    startMonth: new Date(2022, 10),
    endMonth: new Date(2022, 12),
    selectInitialDate: false
})