net-mgmt/py-phonebox-plugin: Add new port

This NetBox plugin is intented for Telephone Number Management.
It currently implements a Number abstraction representing a single
telephone number of an arbitrary format. A Number can consist of valid
DTMF characters and leading plus sign for E.164 support:

• Leading Plus ("+") sign (optional)
• Digits 0-9
• Characters A, B, C, D
• Pound sign ("#")
• Asterisk sign ("*")

Support for Bulk Edit/Delete operations for Numbers and the following
voice circuit types is included as well:

• SIP Trunk.
• Digital Voice Circuit (PRI/BRI/etc).
• Analog Voice Circuit (CO lines/etc).

The plugin also introduces a NetBox REST API extension which is
compatible with pynetbox.

WWW: https://github.com/iDebugAll/phonebox_plugin

Requested by: Mike Geiger (via e-mail)