Handle multiple instances of dev phone

[ayyrickay]

e.g.,

Multiple browser tabs open that are associated with different soft phones

Configurable phone numbers - can change the phone number from the soft phone UI

Example use cases include testing regions (try a UK number, then a US number, or just US numbers from different area codes), etc.

[Swimburger]

While not very approachable, it is doable today by using 2 different Twilio accounts. Here's how I did it in case someone else needs to do it before it is officially supported:

1. Use twilio login to create multiple profiles, each logging into separate upgraded Twilio accounts.
2. Run twilio dev-phone -p YourProfileName
3. Run PORT=3002 twilio dev-phone -p YourOtherProfileName.

Now the Dev Phone runs on port 3001 (default) and 3002, each using a different profile (account).