SdkSandbox: add shell command to start/stop sandbox

Adds support for 'adb shell cmd sdk_sandbox start/stop' with user and
package arguments. The package/user arguments must correspond to an
existing running application.

Bug: 219765182
Test: atest SdkSandboxShellHostTest
Change-Id: I8864fe85c14ae3624fbed8dd850a7c33cbca23a9
12 files changed