Fixup Sim target ID api's

[gerth2]

Currently, in sim, all target id's come back as -1.

https://github.com/mcm001/photonvision/blob/aprilTag/photon-lib/src/main/java/org/photonvision/SimVisionSystem.java#L172

Update sim infrastructure to support custom target id's. Ideally, this should have a nice way for the user to just import the wpilib-provided target locations with a one-liner, rather than have to specifiy each target individually.

[gerth2]

will be closed by https://github.com/PhotonVision/photonvision/pull/512