[18.0][MIG] attribute_set

[bosd]

This PR is inteded as a base for the V19 migration. I've processed some of the review comments from the other pr. If someone seems some value in it to, contribute, merge, overtake, feel free..

Todo besides the migration:

• [ ] - Fix Allow to add values on select fields
• [ ] - Fix attribute_set native field updates during module upgrades
• [ ] - Fix Attribute record duplication to ensure unique names
• [ ] - Fix Attribute error where bool has no startswith method
• [ ] - Fix attribute set placeholder handling to improve compatibility
• [ ] - Fix popup attributes view to show more than 2 characters
• [ ] - Fix view styling and other compatibility improvements