COST-1201: Enable Trino on a per source basis

[dccurtis]

This changes introduces a new environment variable list ENABLE_TRINO_SOURCES. This contains a list (comma separated) of source uuids that will be processed with the Trino processing pipeline.

Testing

1. Start koku-trino with ENABLE_PARQUET_PROCESSING=False. Ingest an AWS source and verify that Trino is not used.
2. Add a GCP source and add the source-uuid to the ENABLE_TRINO_SOURCES list. Restart koku-worker to load variable and hit /download. Verify source is processed with Trino
3. Add OCP source and add UUID to trino list. Verify processing is done with Trino.

Test Results
cost_1201_ut.txt

e2e-deploy: https://github.com/RedHatInsights/e2e-deploy/pull/2899

[codecov]

Codecov Report

Merging #2745 (a7e5df7) into master (0c68f06) will decrease coverage by 0.0%.
The diff coverage is 87.5%.

@@           Coverage Diff            @@
##           master   #2745     +/-   ##
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- Coverage    94.7%   94.7%   -0.0%     
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  Files         289     289             
  Lines       22365   22376     +11     
  Branches     2550    2551      +1     
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+ Hits        21177   21181      +4     
- Misses        717     722      +5     
- Partials      471     473      +2