Avoid double-calls when one is enough.
Avoid unused locals.
Avoid repeating conditions.
Inline single-use expressions.

as the comment (which is removed now) said:

```
        XXX: This method is broken, since "total_size" field is not
        present in the listbox rendering any longer. It should be
        removed.
```

Also:
- make sure that Listbox always knows how many lines are to be displayed.
- add testPagerWithCustomListMethod in listbox_zuite of erp5_ui_test,
which checks that listbox jumping to previous/next/first/last works correctly
for a list method that returns only the elements that the listbox is to render.


/reviewed-on nexedi/erp5!776

Only 'float' supported for the moment. This should cover the case of integers.

Example of 'Sortable Columns' value in a ListBox:

  id | float
  title |

Since there's a fallback to 'Searchable Columns' when 'Sortable Columns' is
empty, the cast type can also be specified there, in order to avoid duplication.

These methods were generated when rendering the ListBox and with the id
of the ListBox in their name. However, a customer reported the following
problem on Accounting Periods ListBox:

  1. Display Accounting Period ListBox on ZEO-1.
       => The ListBox will be rendered and 'listbox_period_list_*' methods will be generated on ZEO-1.
  2.  Click on 'Next Page' button and the user is redirect to ZEO-2 where the ListBox has never been generated.
       => The method does not exist yet and thus a 404 error is raised.

Instead of having one method per ListBox ID, only one is now created (eg
listbox_setPage() for SelectionTool.setPage()) at Zope startup and the
ListBox ID previously defined in the method name is now defined in the
value attributes of the buttons.

When changing listbox display mode (ex: from domain tree to flat list),
remove domain tree from selection, so filtering comming from domain tree
does not apply.
Requested-by: Thierry Brettnacher <tb@nexedi.com>

fixup! ListBox: support rendering empty item as user's input in multi item widget having default values.

fixup! ListBox: support rendering empty item as user's input in multi item widget having default values.

generally speaking, listbox where some editable fields are not listed in fields

Without this, every rendered cells would contain the concatenation of all cells
with same uid (i.e. None) in the previous page, and the size of each cell would
increase exponentially at each update.

fixup! Listbox: do not get stat values on brains by index when we can simply get them by key (ie. column name)

Exception is now a key error

Listbox: do not get stat values on brains by index when we can simply get them by key (ie. column name)

One example is listbox_creation_date in most modules

In some cases 'total_size' was duplicated in selection and request causing listbox rendering to fail.

so that we can call it from restricted environment.

* now Selection for anonymous is stored per its content and its key is embedded in ListBox rendering.
* we no longer provide cookie to each anonymous user.
* thus same URL (i.e. same parameter) for any anonymous user should have the same result.
* Selection storage for anonymous can be still different from the storage for the normal users.

Expired categories should not be displayed

This allows to use the same script for various columns. It is
particularly convenient for listbox used in reports with a list of
columns that could vary depending on data.

Original code failed when 'limit' key is set to None.

Allows telling user whether what he sees is the whole result set, or just
a limited sample of it.

The use of getProperty with a default value was wrong because it does not
display anything if the property is not set and fallbacks to acquisition.

Revert "fix undefined variables"

This reverts commit 77a53809.

Revert "Listbox: calculate a mapping uid -> object once"

This reverts commit 84029c01.

Revert "fix list method returning duplicate uids"

This reverts commit 386b0e6b.

Revert "test for dialog listbox with editable fields"

This reverts commit e046d8f5.

Instead of looping through the list each time.
Also check that the list method does not return duplicate uids.