Instances versioning

[Raphael-Gazzotti]

Currently, instances are stored in the instances/version/ folders, leading to a large number of files when using the main branch or downloading data. This could be optimized by handling them similarly to schema files across different branches, or perhaps through another more efficient approach.

[lzehl]

@Raphael-Gazzotti I don't understand the schemas on the main repository (and I think all target repos) are handled exactly the same way as instances now (namely in folders). However, we can re-discuss of course again if long-term we switch (back) to version branches instead.

@openMetadataInitiative/openminds-developers please provide your opinion here.