PDF Gen - Spike - Pre-work for Construct API(s)

There are a series of work need to be done before API(s) can be created and be usable.
Since, the current pdf_gen saves generated PDFs on a local drive, we need to figure out how to have APIs return the PDF file and HTTP responses, rather than only save PDFs on a drive. (don't need to write code, but need to document this for the actual API functionality work.)
The report-api is also a good reference https://github.com/bcgov/bcros-common/tree/main/report-api
Flask: https://pypi.org/project/Flask/#description

**TODOs**
- [ ] Add dependencies like flask
- [ ] Create a basic structure for APIs like an overall blueprint and folder structure
- [ ] Add a basic API call to check whether it's up and running
- [ ] ~Figure out where to deploy BE service~
- [ ] ~Deploy the BE service (this might be done later, but make sure the APIs work locally (localhost)~
- [ ] Add/Update tests if necessary

Start by reviewing the report-api reference and Flask documentation linked in the issue. Map the requested dependencies, API blueprint and folder structure, basic health-check call, local localhost operation, and any needed tests. Done means the pre-work is documented and the TODOs are addressed or clearly deferred.

Written by the indexing model from the issue text.