Pin active raids

Any currently-executing raid message will be pinned to the top of the Telegram Chat for easy access if the chat is very active.

• As a TG Admin, I want to be able to activate/deactivate the ability for the raid message to be pinned, so we can prioritise what our users focus on while in the chat.

• As a TG User, I want to easily view the current raid by clicking the pinned message, so I can engage on it faster.