Flatten the LocationHierarchy endpoint response

[lincmba]

Add option to return location hierarchy in a list instead of a tree depending on a parameter value

IMPORTANT: Where possible all PRs must be linked to a Github issue

fixes https://github.com/opensrp/fhircore/issues/3161 fixes https://github.com/onaio/fhir-gateway-extension/issues/45

Engineer Checklist

• [x] I have written Unit tests for any new feature(s) and edge cases for bug fixes
• [x] I have run mvn spotless:check to check my code follows the project's style guide
• [x] I have run mvn clean test jacoco:report to confirm the coverage report was generated at plugins/target/site/jacoco/index.html
• [x] I ran mvn clean package right before creating this pull request.

[ndegwamartin]

@lincmba lets also bump up the release version so that we can publish once the PR is ready for merge.