Create device for i22 slits_4

[DiamondJoseph]

i22's slits_4 has different PVs than its other slits, a representation of this device is required along with the existing slits.

Acceptance Criteria

• Specific criteria that will be used to judge if the issue is fixed

[abbiemery]

Once this is fixed, put them back into the plan in i22-bluesky (un-comment them out).

[DominicOram]

We had the same thing on i03 where some of the slits had different PVs and asked controls to add alias' on their side, could we do that here too?

[stan-dot]

Slit x_centre, x_gap, y_centre, y_gap

and name, physical, derived axes: Slit | X_plus, X_minus, Y_plus, Y_minus | X_centre, Y_centre, X_size, Y_size

@DiamondJoseph I extracted that from the issue, I'll call it Slit Special for i22 or something different?