FXOLAT-358: remove empty classes and unused i18n files

src/main/java/org/olat/notifications/handler/forum/_i18n/LocalStrings_ru.properties

-#Mon Mar 02 09:54:19 CET 2009
-newposts={0} \u043D\u043E\u0432\u044B\u0445 \u0441\u043E\u043E\u0431\u0449\u0435\u043D\u0438\u0439

src/main/java/org/olat/notifications/handler/forum/_i18n/LocalStrings_sq.properties

-#Mon Mar 02 09:54:12 CET 2009
-newposts={0} mesazhe t\u00EB reja

src/main/java/org/olat/notifications/handler/forum/_i18n/LocalStrings_zh_CN.properties

-#Mon Mar 02 09:54:03 CET 2009
-newposts={0}\u6761\u65B0\u6D88\u606F

src/main/java/org/olat/notifications/handler/forum/_i18n/LocalStrings_zh_TW.properties

-#Mon Mar 02 09:54:06 CET 2009
-newposts={0} \u7BC7\u65B0\u6587\u7AE0