Running FloodAdapt on Linux

[Jaapel]

In order to run on linux, a few changes were made:

• Needed to update how fiat was built on linux: update pixi env and hooks Deltares/Delft-FIAT#126
• Build SFINCS on linux using: https://github.com/Deltares/SFINCS/blob/main/source/Dockerfile.cpu
• Needed to change some case-sensitive filepaths, for example exposure vs. Exposure
• Needed to make the executable names of fiat and sfincs configurable ( no .exe outside of windows)
• Changes the database to use lowercase folder names where the code also had these

To do configuration I added pydantic-settings to our dependencies (maintained by pydantic maintainers, which is already in our dependencies.)

[Jaapel]

@LuukBlom can you take a look? We should chat on how we will deal with case-sensitive filepaths (with capitalization or without)

[LuukBlom]

I love the new config module!

I only have 1 real comment (about actually validating the paths point to exe/binaries that exist.

Before merging this PR, we need to remove all calls to the old config module in FloodAdapt-GUI as well. (global search for from flood_adapt.config)

The old way using env vars is kind of clunky anyways and this does the same, but much better.

[savente93]

This requires Pixi so moving it to blocked (#485)