Proposal - Migrate PVRTC in favor of more modern ASTC or other compression format

[Jklawreszuk]

Is your feature request related to a problem? Please describe.

PVRTC is texture compression for mobile devices which has been around for a long time. However PVRTC is being considered as obsolete and since we focus primarily on supporting two mobile systems : IOS and Android - both systems encourage the use of ASTC or other format.

From Android developer documentation:

ASTC: Recent format designed to supersede prior formats. More flexible than previous formats due to support for various block sizes. Using this format is a good way to optimize the size of your game.

Percentage of Google Play devices with support : 80%
Older, no longer recommended texture ... formats include: PVRTC
https://developer.android.com/guide/playcore/asset-delivery/texture-compression

[Jklawreszuk]

Looks like the removal of the PVR texture compression format happened a long time ago : 71e9e25 and was replaced in favor of ETC2.
I'll close issue when I check all PVR leftovers after mentioned commit