Add dark/light theme toggle in admin interface for all components

[stevenbal]

Product versie / Product version

latest

Omschrijf het probleem / Describe the bug

To be checked for all components, was added in default project https://bitbucket.org/maykinmedia/default-project/src/d0475f57f24a5d91dc8d89ad3da2be151ab01fca/src/project_name/templates/admin/base_site.html?at=master#base_site.html-28,55

See also: https://github.com/open-formulieren/open-forms/blob/master/src/openforms/templates/admin/base_site.html#L28

It should be added to base_site.html and login.html. I think it would also be good to adapt the light/dark themes from OF to make sure that the dark mode is more presentable

• Open Zaak 🐛 [maykinmedia/open-api-framework#149] Add missing theme toggle in admin UI open-zaak/open-zaak#2048
• Open Notificaties 💄 [maykinmedia/open-api-framework#149] Fix light/dark themes… open-zaak/open-notificaties#291
• Objects API 💄 Fix light/dark themes for admin objects-api#616
• Objecttypes API 💄 [maykinmedia/open-api-framework#149] Fix light/dark themes… objecttypes-api#183
• Open Klant 💄 Fix light/dark themes for admin open-klant#436
• Referentielijsten 💄 Fix light/dark themes for admin referentielijsten#89
• Open Product 💄 [maykinmedia/open-api-framework#149] Fix light/dark themes… open-product#153

Stappen om te reproduceren / Steps to reproduce

No response

Verwacht gedrag / Expected behavior

No response