🩹(frontend) fine tuning v2.2.0

Fix minor issues:
- Add some height to the carret in the editor
- Improve css in mail templates
- Improve images resolution on homepage

src/mail/mjml/partial/header.mjml

@@ -13,7 +13,7 @@
         <mj-all
             font-family="Roboto, -apple-system, BlinkMacSystemFont, 'Segoe UI', Oxygen, Ubuntu, Cantarell, 'Helvetica Neue', sans-serif"
             font-size="16px"
-            line-height="1.3em"
+            line-height="normal"
             color="#3A3A3A"
         />
     </mj-attributes>