Use Lucide icons in the back end (see #7278)

Description
-----------

Implements #7091

<img width="298" alt="" src="https://github.com/contao/contao/assets/1192057/ab780c37-a1ee-4f68-9734-a2fc0fb3efba">

<img width="526" alt="" src="https://github.com/contao/contao/assets/1192057/569e85fa-ff94-4ce5-9130-638deb2c5ed0">

<img width="400" alt="" src="https://github.com/contao/contao/assets/1192057/963a3e4e-4df2-4629-8ca5-130a2c52f441">

<img width="348" alt="" src="https://github.com/contao/contao/assets/1192057/6be535f3-dfe9-42e8-8bfd-f51de8334ee7">

<img width="509" alt="" src="https://github.com/contao/contao/assets/1192057/9343ada9-ac84-4b52-845c-83d5f97d7ff8">

Commits
-------

a617d5ff Use Lucide icons in the back end
cc28f432 Update all icons except the page icons
1b78878f Update the page tree icons
daccd594 Update the placeholder icon
408a154e Fix the "paste in root" icon position and update the import/export icons
e6b2d68c Update the children.svg icon
840af499 Update the layout and modules icon
9254063b Adjust the template diff icon and the table wizard icon
b43708b8 Switch the import and export icons
49a2b57b Update the theme store icon

contao/dca/tl_calendar_events.php

@@ -403,7 +403,6 @@
 		),
 		'source' => array
 		(
-			'filter'                  => true,
 			'inputType'               => 'radio',
 			'options_callback'        => array('tl_calendar_events', 'getSourceOptions'),
 			'reference'               => &$GLOBALS['TL_LANG']['tl_calendar_events'],