Use shared fields in donations form

layouts/_default/donations.html

@@ -6,18 +6,9 @@
       <p style="max-width: 700px" class="h2 mx-auto">
         {{ .Description }}
       </p>
-      <form class="h2" style="border: none; box-shadow: none; margin-top: 0; padding-top: 1em;" action="https://www.paypal.com/cgi-bin/webscr" method="post" onsubmit="return amount.value >= 2 || window.confirm('Your donation is smaller than 2€. This means that most of your donation\nwill end up in processing fees. Do you want to continue?');">
-        <input type="hidden" name="business" value="kde-ev-paypal@kde.org">
-        <input type="hidden" name="cmd" value="_donations">
-        <input type="hidden" name="lc" value="GB">
-        <input type="hidden" name="item_name" value="KDE e.V.">
-        <input type="hidden" name="item_number" value="Donation to KDE e.V.">
-        <input type="hidden" name="currency_code" value="EUR">
+      <form class="h2" style="border: none; box-shadow: none; margin-top: 0; padding-top: 1em;" action="https://www.paypal.com/cgi-bin/webscr" method="post" onsubmit='return amount.value >= 2 || window.confirm({{ i18n "donation-too-small" }});'>
+        {{ partialCached "donation_fields.html" . }}
         <input type="hidden" name="custom" value="//kde.org/community/donations/index.php/donation_button">
-        <input type="hidden" name="cn" value="Enter your name or other publically listed donation message">
-        <input type="hidden" name="cbt" value="Return to www.kde.org">
-        <input type="hidden" name="return" value="https://kde.org/community/donations/thanks_paypal.php">
-        <input type="hidden" name="notify_url" value="https://kde.org/community/donations/notify.php">
         <input type="text" name="amount" value="30" style="vertical-align:middle;text-align:right;" size="4"> €
         <br />
         <input type="image" class="text-white mt-4" name="submit" src="/paypal.png" alt="PayPal" style="vertical-align:middle;">