Collective.eeafaceted.batchactions

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- Added `BaseARUOBatchActionForm`, a class factorizing the action that
`add/remove/update/overwrite` values on an attribute of an object
(originally used for the `LabelsBatchActionForm`) so it is easier to reuse
for other similar actions. `LabelsBatchActionForm` is now based on that
`BaseARUOBatchActionForm`.
[gbastien]
- Activated `delete-batch-action` for zope admin
[sgeulette]

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- Added action to `Update WF role mappings`.
Moved `available_permission` functionality from `ContactBaseBatchActionForm`
to `BaseBatchActionForm` so it is available for any action.
Added `BaseBatchActionForm.available_for_zope_admin` that makes an action
only available to the Zope admin.
[gbastien]
- Make `UpdateWFRoleMappingsActionForm` use
`imio.helpers.workflow.update_role_mappings_for`.
[gbastien]

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- Avoided exception when referer url contains non ascii char.
[sgeulette]

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- Corrected UnicodeDecodeError on transition title.
[sgeulette]

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- Checked permission on context (in ContactBaseBatchActionForm).
[sgeulette]

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- Highlight message about number of elements that will be updated
by the action on the popup.
[gbastien]