Collective.contact.plonegroup

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- Added group_as_str param in organizations_with_suffixes function.
[sgeulette]

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- Added parameter `caching=True` to `utils.get_organization`, this will store
the organization object in the REQUEST and avoid too much catalog queries.
[gbastien]

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- When passing `kept_org_uids` to `utils.get_organizations`,
make sure order is preserved.
[gbastien]

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- Added `BaseOrganizationServicesVocabulary._term_title` to ease override of
rendered term title.
[gbastien]

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- Added `collective.contact.plonegroup.every_organizations` vocabulary, to do
this needed to write `BaseOrganizationServicesVocabulary` from which
`OwnOrganizationServicesVocabulary` and `EveryOrganizationsVocabulary`
inherits.
[gbastien]
- Removed sorting on term title for
`collective.contact.plonegroup.selected_organization_services`, terms are
displayed following selection order in plonegroup organizations like before.
Added new vocabulary sorted on term title and available as
`collective.contact.plonegroup.sorted_selected_organization_services`.
[gbastien]

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- Optimized `OwnOrganizationServicesVocabulary.listSubOrganizations`, do the
catalog query only if current organization contains something.
[gbastien]