Remove the remaining "template" code

I confirmed that all this code is only related to itself. :)

[lorentz:views | Wed 21:22:37] $ grep -r "views_get_all_templates" *
includes/admin.inc:  $templates = views_get_all_templates();
views.module:function views_get_all_templates() {
views_ui.module:    'type' => views_get_all_templates() ? MENU_LOCAL_ACTION : MENU_VISIBLE_IN_BREADCRUMB,
[lorentz:views | Wed 21:22:39] $ grep -r "views_ui_add_template_page" *
includes/admin.inc:function views_ui_add_template_page() {
views_ui.module:    'page callback' => 'views_ui_add_template_page',
[lorentz:views | Wed 21:23:29] $ grep -r "_views_templates" *
modules/node.views_template.inc:function node_views_templates() {
views.module:    $function = $module . '_views_templates';

Checked in #1760284: Rewrite ViewListController to use the core EntityListController. The test coverage for this functionality was removed there, as was the implementation in ViewsUI::init() and ViewsUI::add_template_page(). (See comment #26 in that issue.)