Use location of hydro units instead of bus regions for hydro powerplants units

[davide-f]

Describe the feature you'd like to see

In build_renewable_profiles, hydro time series shall be generated for the x,y location of their powerplants according to the x,y location of the bus, not necessarily its bus region.
See:

pypsa-earth/scripts/build_renewable_profiles.py

Line 560 in 62cab73

if snakemake.wildcards.technology.startswith("hydro"):