Change PR reminders to single simple digest message/list message

[Leystryku]

Is your feature request related to a problem? Please describe. I'm always frustrated when I see a schedules being posted in our organisation because every single Pending Pull Request reminder gets its own message. If there are 30 Pending Pull Requests there are 30 different messages to scroll to. This gets very convoluted very fast.

Describe the solution you'd like The schedule reminders for PRs should be digested. All the PRs should be linked in one big message instead. Instead of Message A PR A, B PR B, C PR C, times the amount of PRs I'd expect to have Message A with a List of PRs.,

Describe alternatives you've considered There could be a toggle for this incase someone doesn't like it. But honestly, this way is MUCH cleaner and better to read

Additional context none needed