chore: update branding in transactional emails (#458)

Signed-off-by: izzy <me@insrt.uk>

crates/core/database/templates/reset-existing.original.html

@@ -9,7 +9,8 @@
     <div class="container">
       <img
         class="ax-center my-10 w-24"
-        src="https://app.revolt.chat/assets/logo_round.png"
+        src="https://stoat.chat/favicon.svg"
+        alt="Stoat Logo"
       />
       <div class="card p-6 p-lg-10 space-y-4">
         <h1 class="h3 fw-700">Password Reset</h1>
@@ -25,7 +26,7 @@
       </div>
       <div class="text-muted text-center my-6">
         This email is intended for {{email}}<br />
-        Sent from Revolt<br />
+        Sent from Stoat<br />
         Made in Europe
       </div>
       <div class="text-muted text-xs my-6 ax-center">