GetChannelById Gets channel by ID from list of channels, sets err if not found.

GetChannelByName Gets channel by name from list of channels, sets err if not found.

GetOptionsMap Converts Discord command options slice to map.

GetTimeDifferenceInDays Gets time difference in days between time arg and current time.

GetTimeDifferenceInDays Gets time difference in days between args.

GetTimeDifferenceInWeeks Gets the time difference in weeks between time arg and current time.

SendMessageInChannel Sends message m in channel c, sets err if failed.