Add devices for i19-2 serial

[noemifrisina]

Shortlist of devices needed (ongoing):

• Attenuator (See Create devices for attenuation on I19 #1007 )
• Pinhole and collimator stage (See Add pinhole and collimator stages control for I19-2 #1508 )
• Diffractometer (Add Diffractometer device of i19-2 #1073 )
• Cryostream
• Backlight (See Add a backlight device on I19-2 #1522 )
• Beamstop (Create a beamstop device for i19 #1067) - NOTE. sometimes used to mount the sample on on eh2)
• Floating stages (used for beamstop on eh2)
• Shutter (this should reuse the already existing hutch shutter with a small addition: check that movement is allowed - #1020)
• Zebra (device exists already, just needs instantiation in beamline file - 1021)
• Eiger detector (See Create an eiger detector device for I19-2 #1523 )
• Tristan detector
• Panda (See Instantiate panda device on i19-2 #1521 )

Use existing ones where possible.

NOTE. To be split in multiple issues/PRs for each new device and linked here.