Add reaction-based timezone converter

[akrantz01]

Add the ability to convert between timezones with messages that have any mention of time in them. It should automatically detect if a time exists in a message (with or without a timezone attached) and add a reaction showing that the timezone can be converted. A DM should be sent to the user with the full message and the converted timezone when a new reaction is added. If they do not have their timezone set, prompt them to enter it (or select if using message components).