ConstMedia constructor Null safety

1. mc_gallery
2. const_media
3. ConstMedia
4. ConstMedia constructor

ConstMedia class

1. Constructors
2. ConstMedia
3. Properties
4. hashCode
5. runtimeType
6. Methods
7. noSuchMethod
8. toString
9. Operators
10. operator ==
11. Static methods
12. buildIcon
13. Constants
14. favStarFilled
15. favStarOutline