Improve error handling / issue warnings

[christian-werner]

Currently, optional data sets once imported to the database remain available (cached) to speed up repeated processing. However, if one imports a new AOI with different CRS, osm_attributes can fail due to projection mismatch (e.g. for the noise layer). Therefore, warnings should be raised early on and re-projection could be offered as an option.

[christian-werner]

Ideal case: run pre-checks before whole workflow starts.

Potential things to check:

• general file structure: data directory (or any other compatible setup / naming) with settings file and mode profiles
• all required files exist (settings / mode profiles, OSM/GIP input, optional input files) and are of supported file type
• required file contents (e.g. attribute columns such as "noise" for noise polygon input") are provided and of supported type (numeric or str; geometry: multi-/Polygon/line/etc.)

Plausibility checks and warnings:

• suitable AOI size for OSM data download via Overpass (direct to e.g. Geofabrik extracts if exceeded)
• general AOI or data input size - feasibility to process (warn if exceeded, as may take considerable amount of time to process)
• projection (mis-)match of available noise / DEM and spatial overlap (to prevent re-using past import of optional layers which are not covering the given spatial AOI extent)

[leaeffertz]

• Warning for faulty usage or srids