Generalize the hr.employee activity plan to any model, allowing to create
activity plan that can be launched on any model.

The activity can now be created in batch by selecting multiple record in the
list view and then clicking on a "clock" icon in a row similarly to the batch
records update (selecting multiple records allows to change for example their
name in batch in the list view). We implement also that functionality for the
plan, allowing to launch a plan on multiple records at once.

We also centralize the launching of activity or activity plan through either
the  "Activities" button in the chatter or the "clock" button in the view list.

Scheduling activity is now taken in charge by a wizard that can schedule a
single activity as well as a plan. We add/update tests for checking that the
wizard is launched with the right record selection (on a single record or a
batch) and add tests for checking the wizard itself.

The plan can be defined through an added menu in the technical admin menu but
also through configuration menu added in the module crm, project.

Technical notes:
In the added wizard, to determine that there is a error, we introduce the
has_error field because we cannot use easily the error field for that. Indeed,
to determine that there is no error, we have to compare it to "<p><br></p>"
(more precisely &lt;p&gt;&lt;br&gt;&lt;/p&gt;) which is not handy and may
change in the future. This is because when we write False on field error and
read it after, we get "<p><br></p>". Instead, we centralize this weird
comparison in the model in the compute method of has_error.

The ActivityListPopover still displays the activity of the record on which it
has been triggered but the button to schedule activity will launch a wizard
that create activities in batch for the selected records if more than one was
selected. For that, the ActivityListPopover component receives now an
additional prop: resIds (selected records) on top of the resId prop (record on
which the popup has been triggered). Note that when the line that trigger the
popup is not selected, the batch mode is disabled to avoid confusion.

We convert the custom plan implementation to use the generic one. As the
generic one can define plans for multiple model. We use the check
dedicated_to_res_model == 'hr.employee' to activate the specific feature for
hr.employee. Indeed, that field contains the model name when the plan is
applicable only for one model.

Task-3390865