remove defaultName method from baked command

[LordSimal]

It was added in #1030 but its not really needed, as it gets statically inflected by the classname anyways.

This makes the user generated code clearer as there is only 1 place where the command name is defined, not 2.

[LordSimal]

According to @ADmad the difference between those 2 is as follows:

the static method provides the default name used for command list without having to instantiate the command. The prop holds the name used when explicitly adding commands using CommandCollection::add() from App's console() hook

[ADmad]

This need to be reverted as setting the default name is required for plugins. As seen in the updated example the default name should be 'test_bake example' (baked using bin/cake command TestBake.Example) but after this change the default implementation of BaseCommand::defaultName() with return example.