[FR] Move templates to the database

[SchrodingersGat]

Rather than storing templates as files, move them into the database:

Advantages

• Easier duplication of templates
• Bypass any caching issues fetching template files from proxy server (currently hacks in place)
• Easier permission controls

References

https://django-dbtemplates.readthedocs.io/en/latest/index.html

Breaking

This would be a major overhaul of the template system, so targeting the 2.0.0 release

[wolflu05]

Maybe we can then also make the uploading of an existing file not required and use some default base template by default?

[SchrodingersGat]

@wolflu05 upload of existing file would be removed entirely I think

[SchrodingersGat]

We can expose a set of built-in template templates to work from