[Tracking] Shorter Decision roll IDs or an option for custom names

[rileyio]

What's happening: Being discussed on Discord and now i'm logging this to continue thinking how best to implement a way to have optional shorthand IDs.

Why is this happening: Decision roll IDs are lengthy, that's agreed. The part of the original idea behind using the ObjectID from the Database index for these was to remove the likelihood of people guessing or easily memorizing and using rolls where their creators maybe wanted them to remain more mysterious.

[rileyio]

From Decision roll features discussion - an idea for this implementation:

• The owner sets a scope value, example: emma
• The owner sets a custom name value (a-z0-9-) that identifies that decision roll and acts as the alias, example: pick-a-card

The above example would be called like: !decision roll emma:pick-a-card

[rileyio]

Added in 7.2.0