Reserved DHCP IP addresses

[timwhite]

Add the ability in the GUI for reserved (static) dhcp addresses. This would probably have to be part of the machine accounts. The changes to CoovaChilli should be minor

[timwhite]

When doing MAC auth, we can give a static IP via the Framed-IP-Address reply attribute.

[timwhite]

For Access-Accept packets, Framed-IP-Address works

select * from radreply where id=5;
+----+-------------------+-------------------+----+-----------+
| id | UserName          | Attribute         | op | Value     |
+----+-------------------+-------------------+----+-----------+
|  5 | 52-54-00-a3-92-86 | Framed-IP-Address | += | 10.1.0.10 |
+----+-------------------+-------------------+----+-----------+