* Use Rust crypto stack universally
Ignore the `feature_rust_crypto` and `RustCrypto.staged_rollout_percent`
settings, and just use RustCrypto everywhere.
* Remove labs setting for rust crypto
* Remove support for legacy crypto stack in `StorageManager`
We're not going to use the legacy stack any more.
* Update docs on `Features.RustCrypto`
* Remove now-unreachable `tryToUnlockSecretStorageWithDehydrationKey`
* Comment out test which doesn't work
* fix typo
* Fix StorageManager checks for rust migration manual opt-in
* fix restricted imports
* Moved utility to check db internals into js-sdk
* fix typos and test names
* more timeout for migration test
Richard van der Hoff