Implement Date range picker demo

[rami-a]

Acceptance Criteria

• Once Implementation of the Material Date Range Picker. flutter#55939 lands, we can create demo for date range picker.
• Demo should follow same pattern as date picker demo and live inside the pickers demo.

[aditya237]

i wanna work on this

[rami-a]

Thanks for the interest @aditya237. flutter/flutter#55939 has landed in master now and you should be able to add a demo for this. Please ensure the demo follows the pattern of our other demos and ensure you add localized entries (this means to add the english strings in the intl_en.arb file and running the l10n script outlined in our README) for each string. Thanks!

[Alabhya268]

I wanna work on this.