ecore_wayland: rename session recovery to align namespace

ecore_wayland: rename session recovery to align namespace

Align out extension naming with other unstable wayland protocols.
The unstable protocols from the wayland-protocols repo are prefixed
with a zwp additionally we keep a e prefix for now as we are still
developing this here. No functional change, just rename.

Pointed out by Derek that the session-recovery interface name is a
bit to generic here.