Initial commit based on latest code of reports folder in akvo-flow repo

* The code is the one present in the `develop` branch on akvo-flow
  repository:
  https://github.com/akvo/akvo-flow/commit/2167f813ce087c58d08f172eac570e17afabdaca
* Renamed the project Leinigen from "reports" to "flow-services"
* Renamed the namespace from "reports" to "akvo.flow-services"