Adds a new custom contact with SIP trunk credentials and other optional fields.
Schema name for multi-tenancy
The phone number to register
"+917418520030"
The SIP termination URI (used for routing)
"popuptesting"
SIP trunk authentication username
SIP trunk authentication password
"2345$"
A friendly name or nickname for the number
"testingg"
The source from which the contact originates
"custom"