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...

[MelissaAutumn]

Technically these should be alternate schedules. Which we could support with some work, but we'd need some UI/UX for displaying multiple schedules for a user to edit.

Along with this we'll need to define what link we want to show in the various non-schedule places (e.g. what schedule is used in the nav bar, or account settings.) Or we could simply link to a landing page which shows a list of available options to book from.

Just some thoughts and ideas!