IPlugin constructor Null safety

1. baguette
2. IPlugin
3. IPlugin
4. IPlugin constructor

IPlugin class

1. Constructors
2. IPlugin
3. Properties
4. hashCode
5. runtimeType
6. Methods
7. addPlugin
8. cleanPlugins
9. getPlugin
10. noSuchMethod
11. removePlugin
12. toString
13. Operators
14. operator ==