Add disconnectTelegramBot mutation

[IvanIvanoff]

Changes

Add a mutation that will disconnect the user and the telegram bot that sends alerts.

mutation{
  disconnecTelegramBot{
    settings{
      hasTelegramConnected
    }
  }
}

When disconnected, the telegram bot will send one last message informing the user
that the bot is disconnected.

Ticket

Checklist:

• I have performed a self-review of my own code
• I have made corresponding changes to the documentation
• I have tried to find clearer solution before commenting hard-to-understand parts of code
• I have added tests that prove my fix is effective or that my feature works