Support Handle Aliases

[wsanchez]

Stonebeard sez:

Some radio traffic clearly identifies a Ranger, but not by that ranger's primary handle.
There are two typical cases: rotating positions (like Khaki or Intercept) and numbered zebras.

When an operator who doesn't know all the LEAL team's details hears a call from Zebra 42, it would be nice if they could enter that (or the Zebra's primary callsign) in the Rangers section of the incident. Secret Clubhouse could support a secret field "alternate callsign" for such a purpose.

Rotating positions like Khaki aren't as useful in the Rangers list and need more situational awareness to resolve.