[react_roles] Bulk Setting of Emoji and Roles to MessageID's

[TwinDragon]

With the exodus of Sinbad an him no longer supporting his cogs going forward, one feature that was immensely helpful when I found out about it was bulk setting of roles to a message ID and the emoji to use for them.

I hope you'll consider adding something like that for react_roles as it'll help with setting up other servers in the future when I use your cog for reaction roles.