Add an optional patch from Etersoft that brings pre-1918 Russian letters to
typographic layout (commonly installed under `share/X11/xkb/symbols/typo').
Option was named ETERSOFT instead of e.g. PRE1918 as their intention was to
maintain several Russian-specific features, not just pre-reform orthography
support. Yes, this also means one day option description should be changed.
While here, move MASTER_SITE_SUBDIR to a more appropriate place in Makefile
and comment out currently unused .include <bsd.port.options.mk>.
Approved by: silence on -x11@