Grafanimate

================
- Rename ``dtstart``/``dtuntil`` to ``start``/``stop``
- Rename ``interval`` to ``every``
- Rename ``AnimationScenario.steps`` to ``AnimationScenario.sequences``
- Improve scope of values for ``every`` parameter. It will now accept relative
humanized timestamps like ``2m30s``, ``1d12h`` or ``1.5 days``.
- Allow relative timestamps / time ranges also for ``start`` and ``stop``
parameters. Accepted are humanized values like outlined above (``2m30s``),
combined with, e.g., ``stop=start+2m30s`` or ``start=-1h, stop=now``.
- Add CI configuration for GHA
- Enable support for relative timestamps with months and years, like ``1y3mo``.
- Avoid ``ffmpeg``'s *height not divisible by 2* errors. Thanks, cure!

================
- Fix attribution signature on worldmap panels
- Add scenario for UBA.LDI.DWD maps
- Add dope sheet blueprint generator spike
- Modernize to Python 3
- Add compatibility with Grafana 6, 7 and 8
- Add possibility to login to protected Grafana instances
- Add possibility to control the sequencing mode (window vs. cumulative)
- Introduce data model for animation scenarios
- Allow loading scenarios from arbitrary Python modules and files
- Optionally define ``grafana_url`` and ``dashboard_uid`` within scenario file.
Corresponding command line parameters ``--grafana-url`` and ``--dashboard-uid``
still take preference.
- When parsing timestamps, allow ISO8801/RFC3339 and Epoch time (``start`` and ``stop``)
- Improve documentation

================
- Revert all image size changes leading to effectively nothing

================
- Attempt to fix image sizes in README once more

================
- Attempt to fix image sizes in README again

================
- Attempt to fix image sizes in README again, see
- https://github.com/github/markup/issues/295
- https://github.com/github/markup/issues/1162