[ENH] Deactivate bot with same auth Token

[Aran30]

This issue got derived from #49.

1. Motivation - In case a new bot agent is submitted with an authentication token which is already used by another bot, the two bot agents will run concurrently and then respond twice to every message. This leads to confusion for the end users and has no concrete use case.
2. Specification - Automatically turn off previous bots which use the same authentication token. (Currently only works if the same las2peer bot agent is used)
3. Finalised state - Submitting new bot with an already used token will turn off the previous bot, thus only answering once per conversation.