Imio.actionspanel

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- Added renderFolderContents section, rendered following flag and/or interface.
[sgeulette]
- In `views.AsyncActionsPanelView.__call__`, remove random value `'_' (ajax_load)`
from `**kwargs` before calling the `actions_panel` or `ram_cached`
`actions_panel.__call__` never work as kwargs are always different.
[gbastien]

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- Changed sections order.
[sgeulette]

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- By default, do not display the `Edit` action when calling
`async_actions_panel`.
[gbastien]

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- Disabled first option of add content button list.
[sgeulette]
- Added apButtonSelect class on select button
[sgeulette]
- Do not link anymore showEdit to showIcons.
Disabled by default showEdit in viewlet.
Render edit as button too.
[sgeulette]

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- Store result of `ActionsPanelView.getTransitions` in `self._transitions` as
it is called several times to make sure transitions are computed only one time.
[gbastien]
- In `ConfirmTransitionView`, store the actionspanel view instead instanciating
it several times as call to `actionspanel.getTransitions` is cached on the
actionspanel view.
[gbastien]

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- In `load_actions_panel JS function`, do not reload in case of error or the
page is reloaded ad vitam. Display an error message instead.
[gbastien]
- When using `string:` expressions, do not insert a blank space like
`string: `` or it is kept once rendered.
[gbastien]
- Manage `IGNORABLE_ACTIONS` the same way `ACCEPTABLE_ACTIONS` so we filter out
first every non relevant actions then we evaluate it.
Removed management of `IGNORABLE_CATEGORIES` and `IGNORABLE_PROVIDERS`, we
only keep `object_buttons` and providers `portal_actions/portal_types`.
[gbastien]