Expose AprilTagFieldLayout origin and dimensions

[amquake]

Is your feature request related to a problem? Please describe.
The AprilTagFieldLayout class is created with specified field dimensions and can have its origin set arbitrarily to modify returned tag poses, but both of these cannot be read from the object.

Usecases:

• Being unable to read the layout's origin impedes the simplest solution to this PhotonVision issue.

• Being able to read the layout's field dimensions could make setting up a PhotonVision simulation field visualization easier for the user.

Describe the solution you'd like
Expose the AprilTagFieldLayout's origin pose and field dimensions.