Remove ability to send key via query string

[rosswhitfield]

Once WebMon (neutrons/data_workflow#169) and WebRef have been updated to use the new method of sending the secret key we can remove the old method.

Ref: 5923: [LiveDataServer] Change API key handling

Short description of the changes:

Long description of the changes:

Check list for the pull request

• I have read the [CONTRIBUTING]
• I have read the [CODE_OF_CONDUCT]
• I have added tests for my changes
• I have updated the documentation accordingly

Check list for the reviewer

• I have read the [CONTRIBUTING]
• I have verified the proposed changes
• best software practices
  • all internal functions have an underbar, as is python standard
  • clearly named variables (better to be verbose in variable names)
  • code comments explaining the intent of code blocks
• All the tests are passing
• The documentation is up to date
• code comments added when explaining intent

Manual test for the reviewer

References

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 86.78%. Comparing base (7b2b256) to head (d74a0d1).

Additional details and impacted files

@@            Coverage Diff             @@
##             next      #22      +/-   ##
==========================================
- Coverage   86.87%   86.78%   -0.10%     
==========================================
  Files          10       10              
  Lines         282      280       -2     
==========================================
- Hits          245      243       -2     
  Misses         37       37              

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