Enable probabilistic list of responses for preset responses

[OrBin]

Preset responses currently receive a preset single response or list of responses.
If a list of responses is given, the response to be sent is chosen randomly from the list.
We want to enable probabilistic selection, for example: the user wants to configure a bot to respond with a certain response in 75% of the times, and with another one in 25% of the times.

Points for thinking:

• How the configuration should look?
• Creating a type (dataclass?) for the probabilistic input (?)
• Validating that the probabilities sum up to 100%

Before implementing this task, please post your suggestion for the configuration structure (an example configuration may be enough).