remove superfluous engine calls

[jrknezha]

This PR removes the code that was creating multiple engines and instead uses the same engine (the one already created within the score table models file) for generating multiple sessions which is the correct desired behavior. This should address problems occurring due to connection limits being hit since the pool size of the engine was not able to be used in the old configuration.

All tests are passing. This does not change any codebase behavior, other files were just removing already unused calls to prevent any future calls to the engine instead of session.

[amschne]

thanks for addressing this, @jrknezha - I'll work with Larry to smoke test our monitoring workflow against this branch to see if it improves performance

[jrknezha]

before merging this PR, we need to also make sure session.close() is being appropriately called for every possible code path where a session is opened.