Add ability to move scintillator into beam

[olliesilvester]

I04's automated OAV centering will require moving the scintillator into the beam position. The current dodal device can only be set to the "out of beam" position.

Acceptance Criteria

• Scintillator always confirms that the aperture scatterguard is parked before attempting to move to scintillator. It errors if the aperture isn't parked
• When moving into beam position, we move Z (horizontal), then wait, then move Y (vertical)
• Scintillator position enums renamed / commented so that it's obvious that "In" means "in beam position"
• Confirm with @aragaod about which other checks we should be doing before moving the scintillator. Eg GDA moves beamstop, gonio, overall gonio position, fast shutter
• Add unit tests to get 100% patch coverage in CI

[DominicOram]

GDA moves beamstop, gonio, overall gonio position, fast shutter

@olliesilvester and I discussed this and agreed that the device itself should only check things that are collision risks. So we need to worry about the aperture being parked but we will cover the other things at the plan level. Covered in DiamondLightSource/mx-bluesky#1305