Generate our own embeds

[ckohen]

Github embeds have some strange arbitrary limits, lets make our own instead.
We'll need embeds for at least the following, duplicate off discord as a starting point

• Branch or tag creation
• Collaborator add, remove, or changed
• Commit comments
• Discussions
• Discussion comments
• Issues
• Issue comments
• Milestones
• Packages
• Pull requests
• Pull request reviews
• Pull request review comments
• Pull request review threads
• Pushes
• Releases
• Registry packages
• Repositories
• Repository vulnerability alerts
• Secret scanning alerts