[test] add end to end tests

There are no test in the repository.

We need to add some end to end tests for all entry point:

- [x] `r2gg:sql2pivot`
- [ ] `r2gg:pivot2pgrouting`
- [ ] `r2gg:pivot2osm`
- [ ] `r2gg:osm2osrm`
- [ ] `r2gg:osm2valhalla`
- [ ] `r2gg:road2config`

TO BE DEFINED : 
- [ ] test framework (suggestion pytest)
- [ ] how to have input data ?
- [ ] how to check results ?