refactor ThreshrControllerSpec to use a table for values

[Jonathan-Zollinger]

Summary

right now the tests use a signle tcinList object.

Why Test?

there could be cases where the tcins irl aren't compatible with our pojo validation.

Proposed Solution

emulate the way place and page are tested, where their data is externally sourced with sensible default file / args

Why Proposed Solution

it's flexible enough to change down the road, even at time of the test, but uses a well rounded default for normal testing.

Alternative

dont change anything, or add more values in-file.

Test Requirements

• [x] test data can be fed in to maven

• 103

• [x] update test readme with added requirements for supplied test data, env vars, etc.

Additional Context

page test with loaded data

Code of Conduct

• [X] I agree to follow this project's Code of Conduct

[Jonathan-Zollinger]

moved #103 to its own task as this data isn't available to be used in testing yet.