Split follower/subscriber milestone notice to seperate notification named 'milestones'

[RoonMoonlight]

Is your feature request related to a problem? Please describe.
Followers and Subscribers milestone notice is part of the livestream notification, and it makes hard to manage the channel.

Describe the solution you'd like
Split follower and subscriber notice to seperate notification named 'milestones'.

Describe alternatives you've considered
None.

Additional context
None.

[JustHumanz]

let me check the code base,it's possible or not
i kinda forget since i'm already not touching the base code for 6 month,lol