Changes for murko found from beamline testing

[DominicOram]

Fixes DiamondLightSource/mx-bluesky#530 and DiamondLightSource/mx-bluesky#147

Built on top of #808 so review/merge that first

Additionally this PR:

• Changes the format of data we store in redis to be just the raw JPEG bytes. This was done after discussion with @aragaod to reduce the memory usage of the redis database.
• Adds a timeout of 30s and so will not stream data for longer than this, FYI @aragaod. We can update this timeout later if needed

Instructions to reviewer on how to test:

1. Confirm tests still pass
2. Confirm device still connects with dodal connect i04

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 95.19%. Comparing base (0ba531c) to head (80652e8).

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #809   +/-   ##
=======================================
  Coverage   95.19%   95.19%           
=======================================
  Files         120      120           
  Lines        4976     4978    +2     
=======================================
+ Hits         4737     4739    +2     
  Misses        239      239           

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