feat: migrate protocol and standards to Package

[TomasArrachea]

This PR ports to main the changes from #3107 and #3094.

This assembles the miden-protocol and miden-standards libraries in build time, along with all account components. The resulting .masp files are accessible from OUT_DIR. Also the packages can be accessed from Rust since impl From<ProtocolLib> for Package and impl From<StandardsLib> for Package are being introduced.

This is not breaking, so a few changes had to be made from those PRs:

1. TransactionKernel::kernel() -> KernelLibrary is kept. Added a TransactionKernel::package() -> Arc<Package> method.
2. Restored the $kernel namespace for the kernel testing library: changed the namespace miden::tx_kernel_core to $kernel. All existing MASM code keeps working.
3. Reverted the kernel masm sources to main's original import spellings (use $kernel::account etc.). The only imports kept on new paths are the modules that physically moved into the miden-protocol-utils library.
4. Added a $kernel::account_id module re-exporting a few procedures from miden::protocol_utils::account_id, restoring an export the old testing library had (it used to be copied into the kernel lib directory at build time).

TODO:

• We also need to port the changes from ci: upload pre-built artifacts #3213 to publish the artifacts with the release. Or, we could just edit the release to add the artifacts manually for this one.