New slash command: /roll

/roll (number) gives a random value between 1-(number), default is 100.

/roll
will result in
/me rolls 73. (1-100)

/roll 3
will result in
/me rolls 3. (1-3)

/roll 0 (or any other invalid parameter)
will result in
/me rolls 23. (1-100)

This is useful especially in DMs (which bots can't reach), as sometimes I would like to randomize some decision being discussed.