[DocsUI, Search]: Introduce V2 of the breadcrumb.

Adds a breadcrumb component that is not tied to the stack.

Bug: 416108180
Flag: com.android.documentsui.flags.use_search_v2_read_only
Test: atest DocumentsUIGoogleTests

Change-Id: I7b388e82a7ae6bcdbcb9cd9713ce506b743ceb00