Add SettingsEntryRepository with some refactoring

1. Refactor SpaEnvironment, lazy init sppRepo and entryRepo
2. Add SettingsArguments with helper functions for arguments build, which is going to replace arguments in SPP
3. Add rootSettingsPages in SppRepo, which is going to replace rootPageNames (TODO).
4. Add button in HomePage to print pages & entries

Bug: 244122804
Test: manual - build Spa gallery
Change-Id: Iccc66f0cb7156c8aa2d9793e296c2a1a2b0e277a