Implement `SnapError`

[Mrtenz]

If a Snap throws a SnapError (standardised error class), the Snap should not crash. This is useful in non-JSON-RPC contexts, such as onTransaction, onCronjob. The SnapError should be serialisable to JSON internally:

throw new SnapError(error);
// { code: -32000; message: error.message; data: { stack: error.stack }}

throw new SnapError('message'); -->
// { code: -32000; message: 'message'; }

throw new SnapError({ code: ...; message: ...; });
// { code: ...; message: ...; }

Related to #1779.

[kenhkan]

From sprint planning: Same solution as https://app.zenhub.com/workspaces/snaps-615b3a7c08d2b20015eb6c4e/issues/gh/metamask/snaps/1779. Setting SP = 0