cannot run risk with RPs bellow 1 year

[panosatha]

FloodAdapt version checks

• I have checked that this issue has not already been reported.
• I have checked that this bug exists on the latest version of FloodAdapt.

Reproducible Example

if an RP of less than a year or in general a decimal RP is configured in the site.toml an error will be returned :
Unknown format code 'd' for object of type 'float'

Current behaviour

FloodAdapt/flood_adapt/object_model/hazard/hazard.py

Line 699 in 369e4cb

map_fn.append(results_path.joinpath(f"RP_{rp:04d}_maps.nc"))

this part assumes that the RP is always an integer.

Desired behaviour

It could be desired that we have RPs bellow 1 year so we should allow for this option.

Task list

• check all parts that this assumption is used
• updated workflow
• write tests

Additional context

No response