## What does this PR do?
Bring back the slot reservation sistem to the new booker
## Type of change
<!-- Please delete bullets that are not relevant. -->
- Bug fix (non-breaking change which fixes an issue)
## How should this be tested?
<!-- Please describe the tests that you ran to verify your changes. Provide instructions so we can reproduce. Please also list any relevant details for your test configuration -->
### Seated event
- [x] Open the new booker in an event with seats
- [x] Select an available slot
- [x] Open the same event and date in other browser, the seat should be already reserved.
- [x] In the first browser come back to the slots views or close the booking form
- [x] In the second browser reload the booking page, the reserved slot should be realeased.
### No seated event
- [x] Open the new booker
- [x] Select an available slot
- [x] Open the same event and date in other browser, the seat should be disabled
## Mandatory Tasks
- [x] Make sure you have self-reviewed the code. A decent size PR without self-review might be rejected.
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