-Fix Panning on Linux is slow
-Add bUseHighPrecisionMouseMovement (true by default) and bUseInterpolationWithManualPanning (false by default) as Graph Editor Settings, set to the current behaviour, but can be switched to allow for a better panning experience on Linux versions of the editor.
#jira UE-209711
#rb ben.hoffman, ronald.koppers
[FYI] jason.walter
[CL 32463490 by jared therriault in ue5-main branch]
