Inroducing new UserManagerState class for docsUI.

This class implements apis to get profiles to be shown in docsUi. It
also provides apis to access other informations related to the
profile like label, badge and cross profile sharing strategy.

Test: atest DocumentsUIGoogleTests:com.android.documentsui.UserManagerStateTest
Bug: 309379547
Change-Id: I73ed1b39ee6899ca5b9c2c1c44329df8cf25b0b1
Merged-In: I73ed1b39ee6899ca5b9c2c1c44329df8cf25b0b1
(cherry picked from commit 7e508851)