[Django] #36549: OpenLayersWidget needs special rules when CSP is enabled

[Django]

#36549: OpenLayersWidget needs special rules when CSP is enabled
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Reporter: Natalia Bidart | Type: Bug
Status: new | Component: GIS
Version: dev | Severity: Release
| blocker
Keywords: | Triage Stage:
| Unreviewed
Has patch: 0 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0
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When using a `OpenLayersWidget` (for example via the `GISModelAdmin`),
which declares custom javascript and css resoures, and if the CSP
middleware is enabled with a commonly secure rule, the JS and CSS
resources are blocked. Full description can be seen here
https://forum.djangoproject.com/t/csp-and-geodjango/41879.

We need to, at least, mention this in the geodjango docs, likely in the
https://docs.djangoproject.com/en/5.2/ref/contrib/gis/forms-api/ section,
extending the existing paragraph:

> OpenLayersWidget and OSMWidget use the ol.js file hosted on the
cdn.jsdelivr.net content-delivery network. You can subclass these widgets
in order to specify your own version of the ol.js file in the js property
of the inner Media class (see Assets as a static definition).

This is a release blocker for 6.0. If we are only doing the docs change,
it has to land before release candidate (i.e. before string freeze)
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Ticket URL: <https://code.djangoproject.com/ticket/36549>
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