Add semi-nonsidereal scheduling

[jchate6]

New semi-nonsidereal (half motion tracking) capabilities have been deployed.
Once this feature is available through the API, we should probably make this the default behavior of neoexchange.

As the current functionality does not have the capability of accounting for an object's drift on the chip, we will need to include multiple configurations within each request to reset the target center based on the maximum target speed within the window.

We will need to decide if we will want to include the option to toggle this feature (and add a sidereal tracking option) to the advanced features tab of the schedule form.