Allow ModuleInfo to be retrieved using apex name.

This adds the apex name (a.k.a. apex module name) to ModuleInfo, and adds a
flag to allow the apex name to be used when calling getModuleInfo.

The existing ModuleInfoFlags was only used for getInstalledModules, so it
has been renamed accordingly.

See go/apex-package-info-discovery

Bug: 141149569
Test: added apex name checks to ModuleInfoProviderTest
Change-Id: I5bcfaa0ef227f3b4eca963e57de4d25c08676c9c