Design.plone.ioprenoto

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- Fixed the manager message stringinterp adapter.
[folix-01]

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- Fix bad stringinterp adapter definition.
[folix-01]
- Remove "description" field to customizable PrenotazioniFolder fields.
[cekk]
- Customize booking-schema endpoint to set *description* as always required.
[cekk]
- Url operator
[mamico]

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- Fix redireect url for anonymous
[mamico]

- Changed label 'uffici correalti'
[mamico]

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- fix booking_url in bookings
[mamico]

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- Move message to contentrule in iocittadino
[mamico]

- Handle custom frontend_domain in notification urls (to fix the /admin problem).
[cekk]

- Fix permission management in PrenotazioniFolder serializer.
[cekk]

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- Fix the prentazione created message.
[folix-01]