Make Keeper delete the message when the reaction is removed

[lima0]

Make keeper delete the DM'ed message if the 🔖 reaction is removed

[iWillBanU]

This

[ddivad195]

In #4 support was added for deleting bookmarks. All new bookmarks will have a ❌reaction that can be clicked to delete it. There is also now a delete command that can be used in the DM by typing "@keeper delete " to remove old bookmarks from before this delete functionality was added.

As of now, removing the reaction to remove the DM isn't easily possible as the bot has no persistent storage, but for now I think the new features added are a good enough solution.