Gamut mapping updates

[facelessuser]

• Add support for adaptive lightness in gamut mapping approaches
• Restructure MINDE plugins
• Make MINDE approach faster when JND = 0
• Allow MINDE to be configured to use different perceptual spaces

[facelessuser]

@gir-bot lgtm

[facelessuser]

We may play around with defaults before release, but the changes are sound.