[YottaDB/Tools/YDBCMake#14] Restore UTF-8 locale dynamic finding

RHEL 7 does not have C.UTF-8, and thus we need to find the locale dynamically.

Also, an earlier commit for YottaDB/Tools/YDBCMake (YottaDB/Tools/YDBCMake@dcbc86f2) changed the location of the M mode file for the sake of Octo's scripts. This was adjusted here as well now that we are incorporating the lastest YottaDB/Tools/YDBCMake commit.