Templates: convenience drop zone to upload files

[apexdodge]

When working with Templates, sometimes we need to simply upload an asset, like a logo, or hardcoded image. While we support the idea of having a File Upload field in raytha attached to content types, there's no convenient way to upload a static asset and have it hosted from Raytha.

Obviously the developer can easily host the static asset elsewhere and just link in, but I think it'd be a nice-to-have to just drop the file into Raytha's template engine and get a URL.

I think ideally, we turn the template editor into a drop zone. If that is too burdensome or difficult, we can add a dropzone to the right sidebar:

[apexdodge]

Sneak peek: https://twitter.com/RaythaHQ/status/1647294414530703362?s=20

To be released with v1.0.6