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.