SF: Move DisplayIdentification to SF/Display

The DisplayIdentification logic is currently located in libs/ui but is
not (and probabably should not) be accessed by external clients of SF.
In addition, it holds display ID fabrication logic that should be
guarded by SF flags as we migrate from port-based to EDID-based display
IDs.

Move the DisplayIdentification logic and associated tests from libs/ui
back to SF.

Bug: 415035569
Flag: EXEMPT refactor
Test: DisplayIdentificationTest + presubmit
Change-Id: Ib96f5becb1d790e60634dec72b21ef15a875c23b