Add Bimorph Mirrors, Slits

[dan-fernandes]

Add Bimorph Mirrors, Slits Ophyd Devices

Instructions to reviewer on how to test:

1. Create + activate venv

To test slits:

1. Start the slit simulator (ask Daniel)
2. Run pytest tests/devices/unit_tests/test_slit_interface.py
3. Ensure all tests pass

To test bimorphs:

1. SSH into BL02J
2. Run pytest tests/devices/unit_tests/test_CAENels_bimorph_mirror_8_channel.py
3. Ensure all tests pass

Checks for reviewer

• Would the PR title make sense to a scientist on a set of release notes
• If a new device has been added does it follow the standards

[DominicOram]

I'm usually a bit ambivalent about squash vs. merge commits but in this case with 300+ commits can we make sure we squash it before we merge?