Partial revert from 2f121c19

/reviewed-on nexedi/erp5!754

/reviewed-on nexedi/erp5!750

In web_site_module/predecessor_test_web_site/section_with_content_page.

This publication_section was already sel on the web section (but seemed not active ??), but not on the web page. Then this commit just adds the missing category and update the web page

Those classes were used by JQuery Mobile.

The tests are exactly the same as for text editor (except there is no
"migration test" which was not really to test TextEditor)

Codemirror app is now using the same mechanism as text_editor. For now, it has
exactly the same features as text editor but it will create "Web Script"
instead of "Web Page" documents. The codemirror mode is forced to "javascript"
and the content type of the document if forced to "application/javascript".

DiffTool: removePropertyList function should be working same for both ERP5 object and dictionaries of ERP5 object properties

Before we use to neglect removing some properties from ERP5 object properties' dict, which led to error in case of use
of DiffTool for Historical Revisions dict. Thus, its important for removeProperties function to act similar in both
cases.

Also, add `base_data` in attribute_set to be removed because `data`, `base_data` and `text_content` are same

This is essential to have better aesthetic of Deepdiff diff for tuples.
In general, we treat iterables as long string so as to bypass the complicated
diff for iterables provided by DeepDiff, but for tuples this was creating a
problem as it was not possible to understand the diff properly.

Hence, by soting them, we get more understandable diff for tuples.

Also, there is no need to override `__diff_tuple` function as it is itself
dependent on `__diff_iterable` which we already override.

Following convention, it makes more sense to use view mode for DiffTool view.
Also, we don't need selection as of now.

Also, update the tests

View wise, the date and path for new version/obvject should be on right side which
in our case is `your_second_date`. Thus, the case where we run diff action on single
object, the right side should show the current version and the left side shoule show
the last version.

/reviewed-on nexedi/erp5!741

/reviewed-on !748

/reviewed-on nexedi/erp5!739

/reviewed-on !740

zope.conf default encoding is also used for responses and converters, so
for consistency we should also force default encoding there.
This is especially useful when running tests, because zope.conf is not
used and default values are used.

https://tools.ietf.org/html/rfc4329#section-7 states that text/javascript is obsolete.

Doesn't really matter in the end because WebPage_viewAsWeb forces the content type.

In HTTP/1.1 , when not specified , charset detault to ISO-8859-1

https://tools.ietf.org/html/rfc2616#section-3.7.1

> media subtypes of the "text"  type are defined to have a default charset value of "ISO-8859-1" when   received via HTTP

Zope adds a charset with default encoding (
https://github.com/zopefoundation/Zope/blob/2.13/src/ZPublisher/HTTPResponse.py#L512-L515 ) but does this only for text/ type, but we serve our javascript as application/javascript

Correctly handle multiple interface declarations

Reduce DOM modification.

Load gadget in an iframe to improve isolation

Delay gadget creation to prevent creating hundred of iframes in parallel, which slow down the browser

Prevent submitting the form if the relation field contains an unknown search string.