Collective.contact.plonegroup

-------------------

- Fix CSS for `display-group-users` view when current user not a Manager
and so does not have link on prefixed icon (user/group).
[gbastien]

-----------------

- Added `PloneGroupUsersGroupsColumn`, a column that displays suffixed groups
and users, to be called on dashboard displaying organizations.
The groups and users are rendered by the `display-group-users` view
that may also be used outside.
By default, as groups and users may be very long to display, it is hidden
in a collapsible `<div>` and displayed asynchronously.
[gbastien]
- Added possibility to disable a `function` (`enabled=True` by default),
this is useful to avoid deleting a `function` and re-adding it after,
sometimes faultly. Adapted `utils.get_all_suffixes(only_enabled=True)`
to only get enabled functions.
Added upgrade step to version `6` to manage new value `enabled=True`
in `functions` stored in the `regsitry`.
[gbastien]
- Remove item `UID` from link in `OrgaPrettyLinkWithAdditionalInfosColumn`
as it is now displayed as additional information by default.
[gbastien]

-----------------

- In `utils.get_organizations`, do not use a `list comprehension` to turn
result of `get_registry_organizations` into a list as it is already the case
(was not the case a long time ago), `get_registry_organizations` returns a
new list and values stored in the registry will not be changed anymore by
default.
[gbastien]

-----------------

- Make the `OrgaPrettyLinkWithAdditionalInfosColumn` also work for `person` and `held_position`.
[gbastien]

-----------------

- As vocabulary `ram.cache` cachekey are generated based on
module/class names, renamed vocabularies
`collective.contact.plonegroup.selected_organization_services` to
`collective.contact.plonegroup.browser.settings.SelectedOrganizationsElephantVocabulary`
and `collective.contact.plonegroup.sorted_selected_organization_services` to
`collective.contact.plonegroup.browser.settings.SortedSelectedOrganizationsElephantVocabulary`.
Added tests showing that cache is correctly invalidated when selected organizations changed.
[gbastien]

-----------------

- Use `collective.contact.plonegroup.sorted_selected_organization_services`
for `settings.IFunctionSchema.fct_orgs`
(field for restricting a suffix to some organizations).
[gbastien]
- In `validateSettings` invariant check if Plone group is empty using
`getGroupMembers` that ignores `<not found>` users instead `getMemberIds`.
[gbastien]