ncurses: only keep the version with widechar support

Only keep the widechar version of ncurses as libncursesw.so.9

Keep the old name to avoid breaking the ABI compatibility (the non
widechar version libncurses.so.9 is not binary compatible with
libncursesw.so.9) since all ports and base are already only linking
against the widechar version we can simply remove libncurses.so.9

Since the .9 version only lived in the dev branch and never ended in a
release, it is simply removed and not added to any binary compat
package.

Add symlinks to keep build time compatibility for anyone linking against
-lncurses