[IMP] survey: improve survey frontend pages

To make the survey even more beautiful than it was, this commit:
- set 'or press Enter' in black instead of primary color.
- align content of inputs (text, number, date, datetime) to the left when
  relevant (readonly mode).
- Add 'Powered by Odoo' on all 'no footer' survey screens.

PR #43568
Task 1972640

addons/survey/views/survey_templates.xml

@@ -16,6 +16,16 @@
         <xpath expr="//header" position="after">
             <div id="wrap" class="oe_structure oe_empty"/>
         </xpath>
+        <xpath expr="//footer" position="after">
+            <div t-if="no_footer" class="py-3">
+                <div class="float-right px-5 py-2 bg-white rounded-left">
+                    <t t-call="web.brand_promotion_message">
+                        <t t-set="_message"></t>
+                        <t t-set="_utm_medium" t-valuef="survey"/>
+                    </t>
+                </div>
+            </div>
+        </xpath>
     </template>
 
     <!-- Main survey template -->
@@ -133,7 +143,7 @@
 
             <div class="text-center mt16 mb256">
                 <button type="submit" value="finish" class="btn btn-primary">
-                    Submit</button><span class="font-weight-bold ml-2 text-primary d-none d-md-inline">or press Enter</span>
+                    Submit</button><span class="font-weight-bold ml-2 d-none d-md-inline">or press Enter</span>
             </div>
         </t>
 
@@ -151,7 +161,7 @@
                     <button t-if="survey.users_can_go_back and page != survey.page_ids[0]" type="submit" class="btn btn-secondary"
                             name="button_submit" value="previous" t-att-data-previous-page-id="previous_page_id">Back</button>
                     <button type="submit" t-att-value="'next' if not last else 'finish'" class="btn btn-primary">
-                        Continue</button><span class="font-weight-bold ml-2 text-primary d-none d-md-inline"> or press Enter</span>
+                        Continue</button><span class="font-weight-bold ml-2 d-none d-md-inline"> or press Enter</span>
                 </div>
                 <div class="col-3">
                     <div class="float-right">
@@ -190,7 +200,7 @@
                                 Continue
                             </t>
                         </button>
-                        <span class="font-weight-bold ml-2 text-primary d-none d-md-inline">or press Enter</span>
+                        <span class="font-weight-bold ml-2 d-none d-md-inline">or press Enter</span>
                     </div>
                     <div class="col-3">
                         <div class="float-right">