Revert "TemplateTool: keep_bt5_id_set can't be None because the is expecting one set or list at least."

This reverts commit b72cc56a.

because it overrides WebPage_viewAsWeb.

Also, expose and document unicity score divisor.

This fixes many different bugs, like random Unauthorized errors when a
knowledge pad is deleted.

When an object is created, calling immediateReindexObject is only a performance
coding crime, which should be negligible since pads are objects that are not
created often. Previous implementation was certainly even less scalable due to
the many extra requests done to wait that new pads are indexed.

If immediateReindexObject is too slow, a distributed cache could be used
instead. This is not trivial and overkill for the moment.

It would be better if we didn't have to rely on the catalog. IOW, data could
have been organized differently so that in ZODB, pads are grouped in containers,
1 per user.

(cherry picked from commit 23da3f0d)

so that :
* the result is stable.
* no permission is required for Supply and Resource only for price calculation.
* no proxy role is required in script.

Because the method internally overrode 'uid' after the first group of objects,
passing a list of uids could make it go berserk and activate all objects in
catalog with an uid greater than those of the first group.

Although searchAndActivate was not initially written to be called with such
list, this commit fixes this instead of forbidding conditions on 'uid',
since it remains useful to easily split & group activities.

CRM: Introduce a script to easily customize the portal type of response events to be selected by default in reply dialogs

Funny things can happen if you have multiple machines and their clock are not
synchronized.

Also, consider the error list when fixit is False only

Add Business Template with Constraints as a example of bt5 with all configuration required to upgrade