Prohibit classes that do not implement any interfaces

[driver733]

Let's create a new Checkstyle rule that will ban classes that do not implement any interfaces.

[0crat]

@krzyk/z please, pay attention to this issue

[0crat]

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[krzyk]

@driver733 This one is quite far going, I see benefits but I'm a bit worried that it result in a bunch of interfaces implemented only by one class. @yegor256 What do you think?