Allow specific lists to be sources for caller-ID data

[Waylo]

For IOS users, there currently isn't an effective way to leverage the Hubspot caller-ID functionality if you have more than 10k contacts. Even Androids can struggle when numbers get big. For sales teams, who are generally only engaged with a relative handful of contacts at any given time, the current caller-ID setup is simply non-functional. 

I suggest allowing active lists to be set as the "preferred source" for app-based caller-ID functions. For example, if I have an active list that keeps my sales rep's most recent 1000 contacts, I would set this list as my source for caller-ID for that rep. So instead of trying to parse 30k contacts every time they get an inbound call, it checks that list first, and they immediately know if an engaged client is contacting them. 

The functionality would be per-user, so it would behave as follows:

1. An admin creates an active list of contacts with specific engagement parameters, (deal has not been closed >60 days, deal owner is X, etc.)

2. An admin would set that list as the "preferred source" for caller ID, and then choose the user/phone number that would use this list. 

On the app side, it would check:

A: Does this user have the app installed and the caller ID function active?

B: Do they have a "preferred call list" of contacts set? 

C: If so, parse that list first when receiving inbound calls. 

This would allow me as an admin to ensure that even as our company grows and the number of contacts in our CRM explodes, I have the ability to get the caller info into my rep's hands without making them jump through hoops or relying on yet another addition to our tech stack.