Add devices for i19-2 serial

Shortlist of devices needed (ongoing):

- [ ] Attenuator (See #1007 )
- [ ] Pinhole and collimator stage (See #1508 )
- [x] Diffractometer (#1073 )
- [ ] Cryostream
- [ ] Backlight (See #1522 )
- [x] Beamstop (#1067) - NOTE. sometimes used to mount the sample on on eh2)
- [ ] Floating stages (used for beamstop on eh2)
- [x] Shutter (this should reuse the already existing hutch shutter with a small addition: check that movement is allowed - [#1020](https://github.com/DiamondLightSource/dodal/issues/1020))
- [x] Zebra (device exists already, just needs instantiation in beamline file - [1021](https://github.com/DiamondLightSource/dodal/pull/1021))
- [ ] Eiger detector (See #1523 )
- [ ] Tristan detector
- [ ] Panda (See #1521 )

Use existing ones where possible.

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