Stabilize Data Format

[matheus23]

Summary

Minimize future migrations by doing data format changes that we already know we'll want to do.

Problem / Need / Opportunity

Changes to WNFS's core data format mean migrations for users and support for both versions from implementations.
We should strive to crystallize the data format for WNFS as soon as possible, so only additional, optional features will be added in the future which don't require migrations.

Success Scenario

We have a stable data format that solves developer needs for a range of different use cases.

Children

• Data Format Stability Tasks rs-wnfs#303
• Add baseName to ExternalContent spec#71
• Switch from AES-GCM to XChaCha20-Poly1305 spec#70
• Specify Blake3's derive_key algorithm instead of SHA3 spec#69
• Remove namefilter.md and add NameAccumulator verification algorithm spec#68
• Update rsa modulus endianess to match most protocols spec#66

ETA: 2023-09-30