Add compatibility_matrix.current.xml for Android Q.

HAL development is starting for Andorid Q, so we need this.

Test: m compatibility_matrix.current.xml
Test: assemble_vintf (but b/78895849)
Test: boot a Pixel device after setting its target-level to 4
    and verify that the compatibility check passes, and the
    file is in the correct location (system/etc/vintf) and that
    the dependencies are setup properly.
Change-Id: I42426d0145a97c719092306abc4f7ce8fa2b51bd