Use DaCe hash system to remove need for FV3_DACEMODE

[FlorianDeconinck]

The only reason FV3_DACEMODE exists is to go around using code hash w/ DaCe to check if the caches need rebuilding. This should be dealt with. Either via caching or git check of hashes, anything that is reliable and fairly fast.
Then do away with FV3_DACEMODE and re-use/lean on a "Recompile" or "Force compile" flag to regenerate caches if need be.
Do away with the double compilation system

Parent: GEOS-ESM/SMT-Nebulae#43

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• System knows when rebuild is necessary. Can be overridden.