Site creation with v0.15.0 fails with older Tableau Server versions

[shinchris]

We had a report that v0.15.0 fails during site creation when using older Tableau Server versions. Workaround for now is to use v0.14.1 of TSC.

Main issue is that all the new site fields are added to the request body, but some of the new fields are not supported by older versions of Tableau Server.

[jacalata]

We definitely need to handle versioning for the site type better, but I don't know what report this is referring to and 3.15 added parameters from before API version 3.0, I'm not sure what might have broken.

We need some explicitly versioned tests for this endpoint.