[Feature] Replace Dave's account with a dedicated bot account

[YesCT]

Summary

Replace Dave's account with a dedicated bot account

https://architecture.lullabot.com/adr/20220426-use-dedicated-accounts-service-integrations/

https://github.com/Lullabot/lsm-examples/wiki/Add-Tugboat is the lsm wiki

https://github.com/Lullabot/lsm-examples/issues/57 has detailed instructions

Problem Statement

What problem does this feature solve? Why is it important?

Be a good example, in case others copy how this repo is set up.
Also, help people notice when Dave the person replies on an issue, and don't ignore those cause people think its "just" a message from the automation.

Proposed Solution

Describe the solution you'd like, including any specific requirements or constraints.

Alternatives Considered

Have you considered any alternative solutions or features?

Acceptance Criteria

• Feature solves the stated problem
• Implementation follows project best practices
• Tests and documentation are updated

Additional Context

Add any other context or screenshots about the feature request here.