SQL now is using new schema

- Add proper error handling in libs/db/query_exec. Uses a catch function after each then to proper capture database errors and report them to the user.
- Add logging the error stack when a database query error occurs.
- Change error message reported in the response when a database query occurs, because the person making the request does not need to know about an internal error in the database.

Signed-off-by: João Victor Tozatti Risso <jvtr12@inf.ufpr.br>

Signed-off-by: João Victor Tozatti Risso <jvtr12@inf.ufpr.br>

Changes in this commit:
- Singularize all routes and components
- Separate different modules into their own source files
- Rename the API module to enrollment and add a more general API module
- Resources that are related to a route, are now under its scope. For
  example, the year range of the enrollment component is now under the
  route /v1/enrollment/year_range
- Implement a thenable function to execute the queries against the
  database to reduce the amount of duplicated code in the application. This
  approach also allows several concurrent queries to run concurrently in the
  same route.