images: add asurada, cherry, corsola chromebooks

These are fully supported with exceptions of:

• FDE
• Audio
• Bluetooth (only on some devices, on other works fine)

However, I'm not going to move them to community for several reasons:

• linux-postmarketos-mediatek-mt81xx is based on linux-next, not stable
• I'm the only maintainer, and I don't have any of these devices

Once we have maintainers having these devices they can fix these issues. Meanwhile, I think these are good candidates to enable prebuilt images.

Here is status of one of each ports:

• asurada: ASUS Chromebook Flip CM3 (CM3200, MT8192) (google-hayato)
• cherry: HP Chromebook x360 13b-ca0xxx (google-dojo)
• corsola: Lenovo 300e Yoga Chromebook Gen 4 (google-steelix)