[Feature Request] IO implementation for FsSpreadsheet DTO

[Freymaurer]

Related: fslaborg/FsSpreadsheet#30

We need to update only ISA changes, without touching any other user content. Therefore we must establish a system to handle this.

For UPDATE contracts we MUST pass all Tables and the metadata sheet. Any table not passed MUST be deleted, any table passed MUST be updated if changed. The metadata sheet passed MUST be updated if changed.

The exact replacement/update of tables MUST be handled/implemented by the specific IO arctrl implementation.

[HLWeil]

Duplicate with #107 ? @Freymaurer

[Freymaurer]

Yes, these were meeting notes 👍