Order non-app window containers.

- Add non-app window tokens to the display child container based on
their base layer so the highest based layer is z-ordered on-top.
- Separated DisplayContent.mNonAppWindowContainers into
mAboveAppWindowContainer and mBelowAppWindowContainer where the former
contains non-app windows that should be z-ordered on-top of all app
windows and the later contains non-app windows that should be
z-ordered below app windows.
- Change wallpaper base layer to 1 so that it is always below all other
window types.
- Add Ime related windows/tokens to DisplayContent.mImeWindowContainers
so that we can track them together
- Use alternative binder token when adding window TYPE_INPUT_METHOD_DIALOG
so that it can properly be associated as an IME token in WM vs. with
system_server or sys-ui token.

Test: Existing tests pass.
Bug: 30060889
Change-Id: Ib53e09af12545868c3741d83aaccb7311c872b41