Create system API for reconciling sub directories of sdk data

PackageManager typically deals with creation of package level
directories via installd. The owners of those storage areas are then
responsible for creating finer grained sub-directories.

SdkSandbox requires per-sdk directories under the sdk package directory
created during package install. This CL opens up a system API via
PackageManagerLocal to enable SdkSandboxManagerService create the
sub-directories on demand.

Bug: 211763739
CTS-Coverage-Bug: 224738104
Test: atest SdkSandboxStorageHostTest
Change-Id: I68259abd16b6767c28093d88e27a52d6c6bdde76