Merge all language in mail module

interface/web/mail/lib/lang/bg_mail_alias_list.lng

interface/web/mail/lib/lang/bg_mail_blacklist_list.lng

interface/web/mail/lib/lang/bg_mail_content_filter_list.lng

interface/web/mail/lib/lang/bg_mail_domain_catchall_list.lng

interface/web/mail/lib/lang/bg_mail_domain_list.lng

interface/web/mail/lib/lang/bg_mail_forward_list.lng

interface/web/mail/lib/lang/bg_mail_get_list.lng

interface/web/mail/lib/lang/bg_mail_spamfilter_list.lng

interface/web/mail/lib/lang/bg_mail_transport_list.lng

interface/web/mail/lib/lang/bg_mail_user_filter_list.lng

interface/web/mail/lib/lang/bg_mail_user_list.lng

interface/web/mail/lib/lang/bg_mail_user_stats_list.lng

interface/web/mail/lib/lang/bg_mail_whitelist_list.lng

interface/web/mail/lib/lang/bg_spamfilter_blacklist_list.lng

interface/web/mail/lib/lang/bg_spamfilter_config_list.lng

interface/web/mail/lib/lang/bg_spamfilter_policy_list.lng

interface/web/mail/lib/lang/bg_spamfilter_users_list.lng

interface/web/mail/lib/lang/bg_spamfilter_whitelist_list.lng

interface/web/mail/lib/lang/de_mail_alias_list.lng

interface/web/mail/lib/lang/de_mail_blacklist_list.lng