Epyt-flow

JOSS submission: Revise paper according to editor's suggestions

- Several bugfixes
- New function `add_species_injection_source()` for injecting MSX species
- Add plot functions to ScadaData

- Serialization: Add functions for loading and saving to .json files
- New function in ScenarioSimulator: get_reporting_time_step()
- Add y_ticks and legend to plot functions (plots can now also be saved to a file)
- More regresion metrics
- Several bug fixes
- Minor changes

- Remove PDA as a default hydraulic model
- Add helper functions to ScenarioControlEnv
- Add functions for placing sensors everywhere
- Add sensors for pump energy consumption and pump efficiency
- SensorConfig: Add function for placing sensors everywhere and test for empty sensor config
- .inp and .msx files can be opened several times (workaround for EPyT bug 54)
- Bugfix: ScenarioConfig for handling relative paths
- Add helper functions to NetworkTopoloy
- Minor fixes

- NetworkTopology: Add helper functions for accessing different types of elements
- Add axis labels to plot_timeseries_prediction()
- Documentation: Add link to source code
- Fix some doc strings

- `NetworkTopology`: Add export to `GeoDataFrames`
- `ParallelScenarioSimulation` returns return values of the callback function
- Several (minor) bug fixes