Wetterdienst

Feature
- Create general Resolution and Period enumerations that can be used anywhere
- Create a full dataframe even if no values exist at requested time
- Add further attributes to the class structure
- Make dates timezone aware
- Restrict dates to isoformat

Fix
- Fix 10minutes file index interval range by adding timezone information

Refactor
- Move more functionality into core classes
- Add more attributes to the core e.g. source and timezone
- Make dates of internal data timezone aware, set start date and end date to UTC
- Add issue date to Mosmix class that actually refers to the Mosmix run instead of start date and end date
- Use Result object for every data related return
- In accordance with typical naming conventions, DWDObservationSites is renamed to DWDObservationStations, the same is applied to DWDMosmixSites
- The name ELEMENT is removed and replaced by parameter while the acutal parameter set e.g. CLIMATE_SUMMARY is now found under PARAMETER_SET
- Remove StorageAdapter and its dependencies
- Methods self.collect_data() and self.collect_safe() are replaced by self.query() and self.all() and will deprecate at some point

Fix
- Bump ``h5py`` to version 3.1.0 in order to satisfy installation on Python 3.9

Fix
- InfluxDB export: Fix export in non-tidy format (230). Thanks, wetterfrosch!
- InfluxDB export: Use "quality" column as tag (234). Thanks, wetterfrosch!
- InfluxDB export: Use a batch size of 50000 to handle larger amounts of data (235). Thanks, wetterfrosch!
- Update radar examples to use ``wradlib>=1.9.0``. Thanks, kmuehlbauer!
- Change wherever possible column type to category
- Increase efficiency by downloading only historical files with overlapping dates if start_date and end_date are given
- Use periods dynamically depending on start and end date
- Fix inconsistency within 1 minute precipitation data where historical files have more columns
- Improve DWD PDF parser to extract quality information and select language. Also, add an example at ``example/dwd_describe_fields.py`` as well as respective documentation.

Fix
- Upgrade to dateparser-1.0.0. Thanks, steffen746, noviluni and Gallaecio! This fixes a problem with timezones on Windows. The reason is that Windows has no zoneinfo database and ``tzlocal`` switched from ``pytz`` to ``tzinfo``. https://github.com/earthobservations/wetterdienst/issues/222