Get redis host and password from environment

[DominicOram]

Fixes DiamondLightSource/mx-bluesky#149

Note: This also needed the following adding to the values.yaml for BlueAPI:

  - name: VALKEY_PASSWORD
    valueFrom:
     secretKeyRef:
       name: valkey-secret
       key: requirepass

Instructions to reviewer on how to test:

1. Confirm matches production at /dls_sw/i04/software/bluesky/scratch/dodal

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 97.67%. Comparing base (2b18524) to head (b280963).
Report is 1 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #913   +/-   ##
=======================================
  Coverage   97.67%   97.67%           
=======================================
  Files         159      159           
  Lines        6589     6590    +1     
=======================================
+ Hits         6436     6437    +1     
  Misses        153      153           

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[DiamondJoseph]

Just noting that the envVar needs to go in the extraEnvVars, in case that half of the ticket is picked up by someone else.

I'd also recommend deploying the Secret as a SealedSecret! Example from p47, docs

[DominicOram]

This also needed the following adding to the values.yaml for BlueAPI:

This is now in https://gitlab.diamond.ac.uk/controls/containers/beamline/i04-services/-/blob/main/services/i04-blueapi/values.yaml?ref_type=heads