Initialize backend

[danr]

current endpoints:

    /db.json
        Pre-calculated survival analysis for the first/front page

    /codes.json
        Tumor type codes -> Tumor type acronym expanded

new endpoints:

    /form_configuration.json
        The different fields that should be in the form +
        the specifics like COAD's anatomical locations and so on

    /filter_database + query describing the filter
        returns the rows matching the filter
        then the frontend calculates the CI + error bounds and draws the plot
        (if this is too inefficient calculate this in the backend)

        pass the query as json object in the body (POST)

[danr]

• [x] Adapt frontend so it uses these endpoints also for the "static" data (db.json, codes.json)

[danr]

Note: coordinate transformations can be done in the frontend

[danr]

:heavy_check_mark: All finished