[IMP] theme_*: remove hardcoded colors on shapes and snippets

Instead now use another custom mapping for the default colors of the
shapes which are used for the default homepage. This allows for the
built page to work with any color palette (especially useful for built
pages in the new configurator) and to handle footer/header connection.

Also change some shapes and default background colors to match what
the preview wanted directly (instead of relying on user asked change as
that would not be handled when generating the page automatically with
the configurator).

Part of https://github.com/odoo/design-themes/pull/2
task-2491890

closes odoo/design-themes#12

Related: odoo/odoo#71665
Signed-off-by: Quentin Smetz (qsm) <qsm@odoo.com>

theme_vehicle/views/customizations.xml

@@ -121,10 +121,10 @@
 <template id="s_table_of_content" inherit_id="website.s_table_of_content" name="Vehicle s_table_of_content">
     <xpath expr="//section" position="attributes">
         <attribute name="class" add="pt88 pb128" remove="pt24 pb24" separator=" "/>
-        <attribute name="data-oe-shape-data">{"shape":"web_editor/Airy/10","colors":{"c5":"400"},"flip":[]}</attribute>
+        <attribute name="data-oe-shape-data">{"shape":"web_editor/Airy/10","flip":[]}</attribute>
     </xpath>
     <xpath expr="//div[hasclass('container')]" position="before">
-        <div class="o_we_shape o_web_editor_Airy_10" style='background-image: url("/web_editor/shape/web_editor/Airy/10.svg?c5=%23CED4DA");'/>
+        <div class="o_we_shape o_web_editor_Airy_10"/>
     </xpath>
 
     <xpath expr="//div[hasclass('s_table_of_content_main')]/section" position="replace">