Implement the connector for emulated vehicles

Some functions are copyed from the original VHAL implementation. The
ones left in the old implementation will be removed after enabling the
Vehicle Connector. Keeping them right now because otherwise it will
break the build.

Bug: b/141493212

Test: since nothing changed in the "active" code, just compiled by `mm`

Change-Id: Ibf525ffe056d6a4c789a7a407eb0b54f61858041