Creation of the remind command

[Mystilund]

Specifications :
This command allows the bot to remind something to someone
The remind is a private message

Syntax :
!!reminds in [Xd] [Xh] [Xm] [Xs] [something]
!!reminds at [XX:XX or XXhXX] [something]
!!remind cancel

For the reminds in :
X for the d parameter : A number, no limit
X for the h parameter : A number between 0 and 23
X for the m parameter : A number between 0 and 59
X for the s parameter : A number between 0 and 59
⚠️ At least one parameter should be set, it's not mandatory to have them all

For the reminds at :
XX:XX or XXhXX : the equivalent of the h and m parameters above

Examples :
!!reminds in 1d 9h 12m Call dad
!!reminds in 10s Call bro'
!!reminds at 17:00 Call mom
!!reminds at 17h00 Call sis'

Implementation :

• The user can have only one remind, if a remind already exist, it will be cancelled
• A timeout should be set and the id returned by the setTimeout should be stored (to be able to cancel it)
• A message of confirmation should be send in the channel as a reply to say something like "The reminder will be sent the [date] at [time]"

⚠️ Careful :
When it's 18:00 and you set a remind at 17:00, it's of course for the next day
The prefix of the command in this description will be "!!" but remember it can be configured