[IMP] website: make tips bioutifoul, and add moar tips

PURPOSE

Make digest email and tips more appealing. The goals of these tips are

  * to encourage the adoption of other apps (Did you know ?);
  * to make Odoo look more fun (Fun tips and tricks, young and dynamic style);
  * to show social proof and increase trust (emphasis on already existing
    projects / customers to);

SPECIFICATIONS

Add a tip about SEO.

LINKS

Task ID 2197417
PR odoo/odoo#51619

Co-Authored-By: Elisabeth Dickinson <edi@odoo.com>
Co-Authored-By: Thibault Delavallée <tde@odoo.com>

addons/website/data/digest_data.xml

+<?xml version='1.0' encoding='utf-8'?>
+<odoo>
+    <data>
+        <record id="digest_tip_website_0" model="digest.tip">
+            <field name="name">Website: Use SEO to get more visitors</field>
+            <field name="sequence">100</field>
+             <field name="group_id" ref="website.group_website_designer"/>
+            <field name="tip_description" type="html">
+<div>
+    <b class="font-16" style="font-size: 20px;line-height: 30px">Use SEO to get more visitors on your website</b>
+    <p class="font-12" style="color:#888888;font-size: 15px; line-height: 25px; margin-top: 0">Odoo helps you to optimize your website and get a better ranking in search engines like Google.</p>
+    <img src="/digest/static/src/img/tips-website-seo.jpg" style="max-width: 580px" width="100%"/>
+</div>
+            </field>
+        </record>
+    </data>
+</odoo>