[Atoms] Add `startDate` prop to `Booker` atom to control initial date

[SomayChauhan]

allowing consumers to dynamically set the initial date shown when the component loads.

[linear]

CAL-5929 [Atoms] Add `startDate` prop to `Booker` atom to control initial date

[Fahad-Dezloper]

Can you elaborate this issue @SomayChauhan