Add URL shortening option for naked VIZ_LINK references for SMS alerts

[jdrummey]

This is something that I thought about when building SMS and never got around to writing up. URLs use up a lot of characters and a unpredictable number of characters (especially when URL parameters are used) so having the ability to have something like a |shortenURL option for VIZ_LINK() content references that used a pre-configured URL shortener would be helpful to trim down the URLs into a known length.