cleanup: use final classes

[COil]

Hello, these classes could be final right? (except the entities)

(just done one example, will do the other if it is OK)

[derrabus]

In my apps, I usually declare all classes final unless I have a good reason not to. I wouldn't mind if the demo app followed this rule as well. 🙂

So 👍🏻 from my side.

[COil]

The only problem I see is that the maker bundle doesn't put the final keyword on controllers.

[OskarStark]

The only problem I see is that the maker bundle doesn't put the final keyword on controllers.

@weaverryan should we use final for controllers in maker bundle?

[GromNaN]

There are good reasons to use final by default. Can we explain with a comment somewhere is this project?

[javiereguiluz]

This practice is very common in Symfony apps, so let's merge this. Thanks Loïc!

[jrushlow]

The only problem I see is that the maker bundle doesn't put the final keyword on controllers.

@weaverryan should we use final for controllers in maker bundle?

@OskarStark symfony/maker-bundle#1539