SetUp Testing Framework - Python Modules

[lincmba]

Succeeds https://github.com/onaio/fhir-tooling/issues/73 Tasks:

• [x] Integrate Pytest into the cleaner and importer modules, ensuring that the modules are configured to run tests using Pytest.
• [x] Create a tests directory within each module and write a set of initial test cases to validate the functionality of the modules.
• [x] Configure GitHub Actions to automatically run the tests on code changes for the cleaner and importer modules.
• [x] Generate coverage report
• [x] Document how testing is performed for the Python modules, including the structure of the test suite and how to run the tests.

Acceptance Criteria:

• [x] Pytest is successfully integrated into the cleaner and importer modules.
• [x] Initial test cases are written and stored in a tests directory for each module.
• [x] GitHub Actions CI is set up for the cleaner and importer modules, ensuring that tests run automatically on code changes.
• [x] Documentation on testing is added, explaining how to run the tests.