Reorganize Sony transforms

[scottdyer]

This PR reorganizes the Sony transforms to keep the unified S-Log3 transforms front and center. This should help clarity to those with any confusion about which transforms should be used that the unified transforms are recommended.

Specifically it:

• Reorganization: Moves older generation color transforms (S-Log1, S-Log2, VENICE-specific) to a newly formed "archive" directory.
  The archive directory is added at the top level of the repository, alongside the vendor directories.
  The rationale for placing it here is in anticipation of additional transforms from other vendors also being deemphasized from active usage in the future. By placing all archived transforms here, there will be a single directory that scripts scraping the repo for new transforms can choose to omit, rather than needing to check for and filter out an archive directory per vendor directory.
• README updates:
  • Adds language recommending the use of the unified transforms for all S-Log3 & S-Gamut3 / S-Gamut3.Cine workflows
  • Adds a note about VENICE-specific transforms being perfectly valid for VENICE and VENICE 2, but that differences are negligible. Therefore for simplicity and consistency, the unified transforms are recommended.
  • Adds a pointer to 'legacy' transforms still being available in the archive directory.

[scottdyer]

Confirmation from Sony received Jan 8 via email:

As a representative of Sony (on this matter), I can approve the following changes on GitHub – which fully reflects our request to clarify how IDTs are recommended to be used with Sony cameras.