Define custom error type for StatusCode.

Define a wrapper class for StatusCode to be used as E in
Result<T, E>. By default E is errorno as defined in linux and does
not print out the correct error message.

Migrate existing Result usage in VHAL to Result<T, VhalError>.

Test: atest VehicleUtilsTest
Bug: 219612366
Change-Id: Ic5369b6035bc46afc4c61da26c4b50f7fa9969d8