[FIX] website, *: fix background layer elsewhere than in a section

*: web_editor

Before this commit, the elements (other than section) and with the
background layer options avaible (shape, color filter, etc.) did not
have the relative position added on their children. So all the
children were hidden behind the layer element which is in absolute
position.

Part of https://github.com/odoo/odoo/pull/58850
task-2312878

X-original-commit: 9c08e119b125b82e2c42dc944920dd8a96789e25

addons/web_editor/static/src/scss/web_editor.common.scss

@@ -770,7 +770,7 @@ blockquote {
     pointer-events: none;
 }
 
-section {
+section, .oe_img_bg, [data-oe-shape-data] {
     @extend %o-we-background-layer-parent;
 }
 .o_we_bg_filter {

addons/website/static/src/scss/website.scss

@@ -373,6 +373,9 @@ font[class*='bg-'] {
 .o_bg_video_loading {
     @include o-position-absolute(0, 0 ,0 ,0);
 }
+.o_background_video, .parallax {
+    @extend %o-we-background-layer-parent;
+}
 
 // Probably outdated
 // Lists
@@ -487,6 +490,7 @@ table.table_desc tr td {
     // Controls
     .carousel-control-prev,
     .carousel-control-next {
+        position: absolute;
         cursor: pointer;
         width: 8%;
         opacity: 1;
@@ -513,8 +517,12 @@ table.table_desc tr td {
         }
     }
     // Indicators
-    .carousel-indicators li:hover:not(.active) {
-        background-color: rgba(255,255,255,.8);
+    .carousel-indicators {
+        position: absolute;
+
+        li:hover:not(.active) {
+            background-color: rgba(255,255,255,.8);
+        }
     }
 
     // Default

addons/website/static/src/snippets/s_color_blocks_2/000.scss

@@ -19,7 +19,6 @@
         }
     }
     [class*="col-lg-"] {
-        @extend %o-we-background-layer-parent;
         padding: 8% 5%;
         padding-top: 8vw; // A flex item cannot have % padding top and bottom (even if it works on chrome)
         padding-bottom: 8vw; // Solution is vw units but we keep 8% as a fallback