[TASK] Remove styles for former ExtensionManager

Deleted CSS files that bring styles for former EXT: em.

Change-Id: Ia8bd3c8971ba5aabb7792a08b4cff577d1f95ec6
Resolves: #48550
Releases: 6.2
Reviewed-on: https://review.typo3.org/21073
Reviewed-by: Wouter Wolters
Tested-by: Wouter Wolters

typo3/sysext/t3skin/stylesheets/structure/module_admin_extension_manager.css

-/* - - - - - - - - - - - - - - - - - - - - -
-Tools > Extension Manager
-
-- - - - - - - - - - - - - - - - - - - - - */
-
-body#typo3-mod-tools-em-index-php a {
-	display: inline-block;
-}
-
-body#typo3-mod-tools-em-index-php table.t3-em-extension-list td {
-	line-height: 17px;
-	padding: 1px;
-}
-body#typo3-mod-tools-em-index-php table.t3-em-extension-list tr.t3-row-header td {
-	padding: 1px 7px;
-}
-
-body#typo3-mod-tools-em-index-php table.t3-em-extension-list td img {
-	vertical-align: middle;
-}
\ No newline at end of file

typo3/sysext/t3skin/stylesheets/visual/module_admin_extension_manager.css

-/* - - - - - - - - - - - - - - - - - - - - -
-Tools > Extension Manager
-
-- - - - - - - - - - - - - - - - - - - - - */
-
-body#typo3-mod-tools-em-index-php .em-listbg1 {
-	background-color: #d8ecd0;
-}
-
-body#typo3-mod-tools-em-index-php .em-listbg2 {
-	background-color: #e6e6e6;
-}
-
-body#typo3-mod-tools-em-index-php .em-listbg3 {
-	background-color: #efefef;
-}
-
-body#typo3-mod-tools-em-index-php tr.bgColor5 td {
-	font-weight: bold;
-}
-
-body#typo3-mod-tools-em-index-php tr.unsupported-ext {
-	background-color: #ffdddd;
-}
-
-body#typo3-mod-tools-em-index-php tr.unsupported-ext td {
-	color: #ff0000;
-}
-
-body#typo3-mod-tools-em-index-php tr.unsupported-ext td a {
-	color: #ff0000;
-}
-
-body#typo3-mod-tools-em-index-php tr td.extstate {
-	color: #fff;
-	font-weight: bold;
-	text-align: center;
-}