[Feature] Auto convert HEIC to AVIF for upload (advanced setting)

[jp-weber]

With the broad support of AVIF, it would be appropriate to implement the feature to convert HEIC to AVIF for modern compatiblitity.

Actual behaviour

In the advanced settings of the app, there is a setting for maximum compatiblitity, which converters the HEIC picture to JPEG.

New behaviour

As new option or as replacement the app should be able to convert the HEIC to AVIF format.