Resolve "Create page for adding bookings"

What does this mr do?

• Add screen for bookings
• TimeSlotConfig in the databaseloader

A page has been added where guests can select a timeslot. Currently the time slots are ordered in a table, for the future it might be nice to group them for those which are at the same time, but this will depends on the design of the IO students.

Functionality for reducing the number of timeslots available when claiming a timeslot does not yet work.

Screenshots

before

after

Does this MR meet the acceptance criteria?

• I have added a changelog entry to reflect the significant changes I made.
• Tests were created to test the feature.
• I have updated the documentation accordingly.
• I adhere to the style guide.

closes #43 (closed)