Support Multiple Scheduling Options

[ryanleesipes]

Is your feature request related to a problem? Please describe.
Right now I only have my "General Availability" link to send to folks, which I've defined as a 30 minute meeting 3 days out. There are times when I want to send an "Urgent" link that would allow folks to grab my time on my calendar as short as 12 hours in advance. Additionally, I would like to have options for different lengths of meetings.

Describe alternatives you've considered
The current system means I have to change the settings of my only "availability", which isn't ideal because what I have set there isn't for special circumstances, it is intended for normal meetings.

Additional Context
You see this functionality in other tools, we really need a name for these - should see what @laurelterlesky thinks...