Databallpy

- Added databallpy_events to get a unified type of event data
- Added individual player possessions (Adrienko et al., 2016)
- Added pressure feature (Herrold et al., 2022)
- Added differentiate features with filters
- Optimized loading in tracab tracking data
- In quality checks, fixed some minor bugs.

- Added way to save Match objects, and to load saved Match objects
- Fixed bug in opta event data, own goals are now parsed as seperate event type
- Added parser for Inmotio tracking data
- Added parser for Instat event data
- Added quality checks for the data, raises warning if quality is not good enough

<<<<<<< HEAD

- Added parser for Metrica, including an open dataset
- Added functionality to synchronize tracking and event data
- Added functionality to plot events
- Fixed bug, now both tracking and event data are normalized in direction
- Fixed unexpected behaviour, all date related objects are now datetime objects

- Hot fix to make documentation visible.