Prepare release 2.15.0

[veenstrajelmer]

Todo:

• improve astrog outofrange warning message #429
• move to pixi #431
• ProcesType metadata was added as metadata in metadata_from_ddlpy() in update hatyan after ddlpy update to new waterwebservices #410. It would be consistent to use this to distinguish between astro/meas instead of WATHTE/WATHTBRKD in the entire codebase. And to set it as obligatory metadata in metadata_from_diablocks(). Consider removing WATHTBRKD from entire codebase, requires adding ProcesType everywhere, also when reading/writing wia/diafiles. If so, metadata dict will change (new procestype), so also run all example scripts.
• Add support for WIA files #96

Optional:

• improve netcdf HWLW output #82
• Issues with auto-derive xfac from manual metadata #197
• Generate statistics csv #235
• remove DeprecationWarning filter for pyparsing/matplotlib in pyproject.toml again (required dropping Python 3.9 support)
• consider removing origin attribute throughout code, what is added value? >> useful for component merging, but consider adding origin only upon analysis
• discuss deriving extremes: is spline fit required or 1min prediction ok? Is it also used (and stable) for waterlevel measurements or different algorithm? >> currently HWLW are derived from 10min measurements with MELISSA