SF: Generalize display management

This CL enables SF to manage an arbitrary number of physical displays.
Previously, displays were identified by 32-bit IDs, where 0 is the
internal display, 1 is the external display, [2, INT32_MAX] are HWC
virtual displays, and -1 represents an invalid display or a non-HWC
virtual display.

If the HWC provides display identification data, SF now allocates 64-bit
display IDs for physical and HWC virtual displays. The IDs are expressed
using an option type, where the null value represents an invalid display
or non-HWC virtual display. Without HWC support, SF falls back to legacy
behavior with at most two physical displays.

The dynamic display IDs are translated to the legacy constants at the
SF/DMS boundary, as a stopgap until the framework is generalized.

Bug: 74619554
Test: Connect 3 displays and create virtual displays on HWC 2.2 and 2.3
Test: libsurfaceflinger_unittest
Test: SurfaceFlinger_test
Change-Id: I0a4a57b6ab7de2dbcf719a4eb1a19a133694012e