Converting exposure files to previous OED version before running model

[ncerutti]

Issue description

See PR #OasisLMF/ODS_Tools#66, which introduced OED (Open Exposure Data) version support in oed_tools.

If a model configuration includes a list of supported OED versions and the OED schema contains values that must be converted to ensure compatibility with those versions, then the exposure data will be converted to the latest compatible version before running the model.

Example

Version 2.2 introduced OccupancyCodes 1070, 1071, 1072, 1073.
If the model configuration file includes "supported_oed_versions":["2.0"], then any entry in the exposure files referring to these codes will be replaced by their fall back codes (1070 -> 1051, 1071 -> 1056, etc.). Fall back codes are predefined values that provide backward compatibility for newer OED versions.

Notes

This step should be skipped either if the corresponding option is set in the model configuration file (e.g., "convert_oed_version"="False", or if the corresponding argument is passed (e.g., --versioning false).