AVIF has quality setting too

[pinanew]

Description

AVIF has quality setting too, currently used only default value 75.

Screenshots/videos:

Checklist:

• [x] I have read contributing wiki page
• [x] I have performed a self-review of my own code
• [x] My code follows the style guidelines
• [x] My code passes tests

[w-e-w]

additional commits

• fix exif_bytes referenced before assignment
• update opt.jpeg_quality description to include avif