Descriptive bot names from class name or docstrings or class attributes

The old BOTS file used very descriptive and comprehensible bot names. With #1751 the names are derived from the class names which comes with major changes in the bot names. To get descriptive names, we can either put the names in a docstring or use class attributes to store the bot name. Then intelmq.lib.utils.list_all_bots can use this name if it exists, and fallback to the class name.

I propose to add a method bot_class_long to intelmq.lib.bot.Bot which simply returns type(self).__name__ and which can then be overridden by child classes.
(bot_class_long because the term name already means something else and the term type refers to the four types of bots)