Redturtle.prenotazioni

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- Remove the notification gateways allowing cross logics
[folix-01]

- Add id in booking serializer
[mamico]

- Handle `modified_after` parameter in bookings endpoint.
[cekk]

- Add booking_code as catalog metadata.
[cekk]

- [BREAKING] Move code generation and managers email notification from event handlers into booker.
[cekk]

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- Revert last changes to avoid incompatibility.
[cekk]

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- Register event handler for IObjectAddedEvent instead IObjectCreatedEvent for code generator.
[cekk]

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- Performance improvements: changed functions: `hm2DT`, `value_hr`, `get_values_hr_every`
[mamico]

- Perfomance refactoring for available-slots view
[folix-01]

- Split booking notification gateways to 'App IO', 'Email' and 'SMS'
[folix-01]

- remove unused contentrules
[mamico]

- Add booking reminder emails.
[folix-01]

- Move code generation to adapter, to be more customizable.
[cekk]

- Add customizable email from in PrenotazioniFolder contents.
[cekk]

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- Add creation and modification dates to serialized booking
[folix-01]

- Add fullobjects in bookings
[mamico]
- Use the <PrenotazioniFolder>.holidays constraint.
[folix-01]

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- add content-transfer-encoding customization
[mamico]