Create versions directory and symbolic links for frameworks

[mugikhan]

Description

The framework bundle for powersync-sqlite-core.framework was causing a "Malformed Framework" error because it was missing the required symbolic links that are part of the standard framework structure (Framework Anatomy).
The framework lacked the Versions directory and symlinks (Versions/Current and powersync-sqlite-core), which are necessary for proper framework versioning.

The changes include the following:

Versioned Framework Directory Structure:

• A Versions directory is now created within the framework bundle.
• The binary is placed in Versions/A/powersync-sqlite-core.
  Symlinks:
• A Versions/Current symlink is created, pointing to Versions/A.
• A root-level symlink (powersync-sqlite-core) is created, pointing to Versions/Current/powersync-sqlite-core.

Directory structure

Testing

I've tested that the new framework structure works by deploying a test app to TestFlight ensuring there are no "Malformed Framework" errors.