Update edit_user form page and also minor updates to Form and ArraIO

login_user_id is unique if not null (as index, constraint only with
PostgreSQL 15)
login_user_id_revalidate_after is not longer not null and default set,
no need for this

DB\Extended\ArrayIO:
add sql_read for datetime fields to change amount of data (eg only up
to minute) with to_char() method. sample: YYYY-MM-DD HH24:MI
Add date/datetime/emptynull for setting empty fields to null and not
empty string

Output\From\Generate:
Remove all fill for spacer and change them to placeholder html types.
Add datetime check next to date, time only checks

edit_user Admin Form:
add all new columns there

www/includes/templates/admin/edit_elements.tpl

@@ -32,7 +32,10 @@
 			<input type="hidden" name="HIDDEN_{$element.data.name}" value="{$element.data.HIDDEN_value}">
 		{/if}
 		{if $element.type == 'date'}
-			<input type="text" name="{$element.data.name}" value="{$element.data.value}" size="10" maxlength="10">
+			<input type="text" name="{$element.data.name}" value="{$element.data.value}" size="10" maxlength="10" placeholder="YYYY-MM-DD">
+		{/if}
+		{if $element.type == 'datetime'}
+			<input type="text" name="{$element.data.name}" value="{$element.data.value}" size="16" maxlength="16" placeholder="YYYY-MM-DD HH:mm">
 		{/if}
 		{if $element.type == 'textarea'}
 			<textarea name="{$element.data.name}"{if $element.data.rows} rows="{$element.data.rows}"{/if}{if $element.data.cols} cols="{$element.data.cols}"{/if}>{$element.data.value}</textarea>