add bootstrap5 templates

[PetrDlouhy]

I have added templates for Bootstrap 5. The only difference, that is really needed is renaming of data-toggle to data-bs-toggle.

But I also added the {{ extra_class}} attribute which I found very handy. It can be used this way:

{% with extra_class="flex-wrap flex-row" %}
   {% sitetree_menu from "footer_3" include "trunk,topmenu" template "sitetree/menu_bootstrap5.html" %}
{% endwith %}

[coveralls]

Coverage remained the same at 95.827% when pulling d3fe2d4 on PetrDlouhy:bootstrap5 into 8685369 on idlesign:master.

[idlesign]

Thank you.

This class thing could be useful indeed, so I'd like to ask you also to update the docs: to mention this extra class and new templates. https://github.com/idlesign/django-sitetree/blob/master/docs/source/templatesmod.rst

And another thing: it'd probably more flexible if we call that extra_class_ul.
This way we'll be able to add extra_class_li etc. in future if decided.

[idlesign]

Typo here — extra.
Also missing the new templates listing.

[PetrDlouhy]

@idlesign I have changed the PR to your suggestions.

BTW There is 1 more thing, for which I have to override the whole template. I am using font-awesome icons, so I need to make the item.title_resolved safe (see #91 (comment)). I don't think, that is wise to add something like that to templates generally (in some systems users could have access to the sitetree editing). But I can either do something like

{% block title %}{{ item.title_resolved }}{% endblock %}

so that only this part of the template needs to be overriden, or it can be done by some settings (like SITETREE_FORCE_SAFE=True).
What do you think is better?

[idlesign]

@idlesign I have changed the PR to your suggestions.

Thank you. There's the pending issue though — #304 (comment)

I don't think, that is wise to add something like that to templates generally (in some systems users could have access to the sitetree editing).

This has no connection to Bootstrap template. Let's open another issue to discuss it, if it's required. Yet, I'd rather try to play with mark_safe() somehow before anything else.

[PetrDlouhy]

@idlesign Sorry about the pending issue - I didn't push it properly yesterday.

The issue regarding HTML in title_resolved is here: #305

[idlesign]

Thank you. Merged.