[deploy] Fix helm config and maintenance scripts

[imnasnainaec]

• Updates deploy_qa.yml workflow's step for removing old images
• Restores pullSecretName in deploy/helm/thecombine/values.yaml
• Removes one-shot maintenance script db_update_audio_type.py
• Restores python3 shebang in maintenance scripts
• Updates kubernetes documentation, including prep for OpenTelemetry

This change is 

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 74.66%. Comparing base (6a9de6e) to head (3fae27e).
Report is 1 commits behind head on master.

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #3404   +/-   ##
=======================================
  Coverage   74.66%   74.66%           
=======================================
  Files         280      280           
  Lines       10856    10856           
  Branches     1317     1317           
=======================================
  Hits         8106     8106           
  Misses       2377     2377           
  Partials      373      373           

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backend	83.84% <ø> (ø)
frontend	66.63% <ø> (ø)

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[jasonleenaylor]

.github/workflows/deploy_qa.yml line 95 at r2 (raw file):

              if [[ $VC > 0 ]]; then REM="v${VA}\.${VB}\.$((VC - 1))-.*"
              elif [[ $VB > 0 ]]; then REM="v${VA}\.$((VB - 1))\..*"
              else REM="v$((VA - 1))\..*"; fi

This is some fancy bash, I had to look it up. Very effective though.
I think a comment explaining what is being removed here would help future maintainers

Code quote:

          if [[ $TAG =~ ^v([0-9]+)\.([0-9]+)\.([0-9]+)-.* ]]; then
              VA=${BASH_REMATCH[1]}; VB=${BASH_REMATCH[2]}; VC=${BASH_REMATCH[3]}
              if [[ $VC > 0 ]]; then REM="v${VA}\.${VB}\.$((VC - 1))-.*"
              elif [[ $VB > 0 ]]; then REM="v${VA}\.$((VB - 1))\..*"
              else REM="v$((VA - 1))\..*"; fi

[jasonleenaylor]

Reviewed 2 of 11 files at r1, 21 of 21 files at r2, all commit messages.
Reviewable status: complete! all files reviewed, all discussions resolved (waiting on @imnasnainaec)

[jasonleenaylor]

Reviewed 1 of 1 files at r3, all commit messages.
Reviewable status: complete! all files reviewed, all discussions resolved (waiting on @imnasnainaec)