Added option for initialDates

[mustafashykh]

Add Initial Calendar View Date Support

Description

Added the ability to set initial calendar view dates without pre-selecting them. This enhancement allows users to specify which months should be displayed in the left and right calendars when the date picker first opens, without affecting the date selection.

New Features

• Added initialDates input property that accepts an array of two dates [leftCalendarDate, rightCalendarDate]
• Supports both string dates and dayjs objects as input
• Maintains existing date selection functionality
• Falls back to current month and next month if no initial dates are provided

Usage Example

<ngx-daterangepicker-material [initialDates]="['2024-01-01', '2024-02-01']" >
</ngx-daterangepicker-material>

Changes Made

• Updated daterangepicker.component.ts to handle initial dates
• Updated daterangepicker.directive.ts to pass through the new property
• Maintained backward compatibility with existing functionality

Testing

• Tested with string dates
• Tested with dayjs objects
• Verified that date selection works as expected
• Verified fallback behavior when no initial dates are provided

Breaking Changes

None. This is a non-breaking enhancement that maintains full backward compatibility.