Add focusing mirrors to I19

[noemifrisina]

Fixes #1775

Add focusing mirrors to I19-optics, with additional piezo control. They use this to steer the beam during alignment by setting a voltage to the piezo actuators.

• Create a new FocusingMirror device with a piezo actuator
• Instantiate real device in i19-optics
• Create an access controlled device to set the piezo actuators voltage
• Instantiate this device in i19-1 and i19-2

Instructions to reviewer on how to test:

1. Run dodal connect on i19-optics, i19-1 and i19-2 and verify it all works
2. Run tests

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
• If changing the API for a pre-existing device, ensure that any beamlines using this device have updated their Bluesky plans accordingly
• Have the connection tests for the relevant beamline(s) been run via dodal connect ${BEAMLINE}

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 99.11%. Comparing base (f8d8a2b) to head (d855274).

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #1782   +/-   ##
=======================================
  Coverage   99.11%   99.11%           
=======================================
  Files         279      280    +1     
  Lines       10626    10672   +46     
=======================================
+ Hits        10532    10578   +46     
  Misses         94       94           

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.