SAMM to SAMM mapping and migration support

[maximbaele]

Description:
If we are to release the next version of SAMM, we need to provide a SAMMv2.x to SAMMv3.x mapping, as well as support to help migrate scores and/or roadmaps.

Acceptance criteria:

• A SAMMv2 to SAMMv3 mapping is created
• Migration documentation, including guidance on interpretation and score deltas is provided
• If we decide to support migrations with tooling, the toolbox offers a way to migrate data

Are there any known dependencies between this issue and any other issues?
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Are there any outstanding questions?
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