[Web] Fix require_once to always include document root

[Web] Add system mails (send mails to all mailboxes via LMTP)
[Web] Allow to add more administrators
[Web] Fix domain administrator editing
[Web] Remove some foreign keys
[Web] Remove username from API
[Web] Remove more .php extension from code
[Web] More minor fixes

data/web/lang/lang.lv.php

@@ -206,8 +206,6 @@ $lang['mailbox']['target_address'] = 'Doties uz  adresi';
 $lang['mailbox']['username'] = 'Lietotājvārds';
 $lang['mailbox']['fname'] = 'Pilns vārds';
 $lang['mailbox']['filter_table'] = 'Filtra tabula';
-$lang['mailbox']['yes'] = '✔';
-$lang['mailbox']['no'] = '✘';
 $lang['mailbox']['in_use'] = 'Lietošanā (%)';
 $lang['mailbox']['msg_num'] = 'Vēstule #';
 $lang['mailbox']['remove'] = 'Noņemt';
@@ -404,8 +402,6 @@ $lang['admin']['save'] = 'Saglabāt izmaiņas';
 $lang['admin']['admin'] = 'Administrators';
 $lang['admin']['admin_details'] = 'Labot administratora detaļas';
 $lang['admin']['unchanged_if_empty'] = 'Ja nav veiktas izmaiņas, atstājiet tukšu';
-$lang['admin']['yes'] = '✔';
-$lang['admin']['no'] = '✘';
 $lang['admin']['access'] = 'Pieeja';
 $lang['admin']['no_record'] = 'Nav ierakstu';
 $lang['admin']['filter_table'] = 'Filtru tabula';