for now used in solver configuration only

Using an em html tag is enough to have to display the explanation
message differently, not need to wrap it in paranthesis, which does not
look so good in some languages.

Listbox supports setting '' (empty string) as an URL column to disable
the link, but None was never really supported, even though it worked in
the old UI.
When setting using the "key | value" form of formulator, if value is
empty, it's not None but an empty string. This is also what we test in
portal_tests/listbox_zuite/testUrlColumns

formulator passes arguments, no need to look in request by hand. Also
this makes scripts easier to test if passed arguments are used.

This is required to be able to use solve divergence action

When using checkPythonSourceCode integrated in the source code editor,
for a scenario where developer edit a component and save we can benefit
from caching the check message for the source code content, because the
same check that the one happening in the editor will happen when the
component is saved.

This cache varies on:
 - "component_packages" cache cookie which is reset every time some
component code is edited.
 - zope startup time to take into account editions of file system code.
This assumes that after reseting file system code zope will be
restarted.
 - portal_type, because the checks performed by this function also
depend on portal type.

this makes completions works when using Ctrl+space

This makes "Format Document" / "Format Selection" work.

because pylint is a bit slow on large components, debounce every 2
seconds. TODO: this is too slow.

For now this is just the portal_url, but I'm thinking it could be a
proper tool.

IIRC the only thing needed is that ERP5TypeTestCase.getPortal is an
ERP5Site

on very large python files (>1000 lines) sometimes they queue up and we
have to wait for all requests that were queued by zope.

XXX maybe this does not happen when accessing through haproxy/apache, I
am observing this when hitting zope directly

because title is acquire from id, we want to edit title first for the
case where we change ID, otherwise saving would save the old ID as
title.

 * don't set "hide rows on no search criterion", this should not display
too much and search is broken.
 * use preference to get number of lines

This can hide bugs, especially when updating business templates.

TODO: if we drop this we can also drop the command line flag

Until now, a reset was performed even though ZODB Components were not created or
replaced. Introduce a new installation hook to avoid those useless resets.

When installing bootstrap bt5s, erp5_base, erp5_simulation: 33 => 12 resets.

Improve consistency with document view

The changes from nexedi/erp5!1158 were not so good in ERP5JS, it was good to have the action here:

![stock browser dialog showing Stock as a view action](/uploads/0e9495858295016926da484b6c5fa68f/image.png)

and not under "Exports", because this is not an export, it's an interactive report.

Also, the "Stock" button is not easy to understand, this is not an action, so we use only an update button now:


![stock browser dialog with only an update action, no action](/uploads/71f40b3e2e951f3c95f7ff885dd91090/image.png)

Also, the action button in movement history was confusing, it's not a button where user have to click. It was like this, with a confusing button (but this button was sometimes useful, because with this button we can go back to stock browser):

![movement history before](/uploads/75450d7fbfe1f208ca17e14b22059b38/image.png)

Now it's like this, the button is not here, but since the action is now listed in Views, it's easy to go back to stock browser:

![movement history after](/uploads/d66d28f1fc66b69b84baba6d88574afc/image.png)

See merge request nexedi/erp5!1179

Since 5eb06085 (erp5_web_renderjs_ui: do not display submit and cancel if action is empty in form_dialog., 2020-06-10) ERP5JS does not display submit button, this continues in this direction to:

 - Apply the same possibility in xhtml_style to not show a submit button when there's no action. In xhtml_style we show the cancel button using the same rules as everywhere else.
 - Fix error in ERP5JS for dialogs with only an update action but no action.

See merge request nexedi/erp5!1181

Change login button to comply with Google's branding guidelines.

Add support for google login in ERP5JS.


See merge request nexedi/erp5!1166

See merge request nexedi/erp5!1171

There's nothing wrong in having more than one listbox in a dialog