Add Overmind to bin/dev, implement Heroku deploy, and clean up Gemfile

[SethHorsley]

Description

This PR introduces several improvements to our development and deployment workflow:

1. Integrates Overmind into bin/dev for better process management
2. Implements Heroku deployment capabilities
3. Cleans up and optimizes our Gemfile

Changes

1. Overmind Integration

• Added Overmind to bin/dev script
• Updated development workflow to utilize Overmind for process management

2. Heroku Deployment

• Set up necessary configurations for Heroku deployment

3. Gemfile Cleanup

• Changed the way we reference the github repo for the phlex_ui gem.

[cirdes]

Looks good!!