add vivaldi provider

closes: https://framagit.org/dystopia-project/simple-email/-/issues/29

app/src/main/res/xml/providers.xml

@@ -1,15 +1,19 @@
 <?xml version="1.0" encoding="utf-8"?>
 <providers>
-    <provider name="disroot.org">
+  <provider
+      name="Disroot.org"
+      link="https://howto.disroot.org/en/tutorials/email">
         <imap
-            host="Disroot.org"
+            host="disroot.org"
             port="993" />
         <smtp
             host="disroot.org"
             port="587"
             starttls="true" />
     </provider>
-    <provider name="Riseup">
+    <provider
+        name="Riseup"
+        link="https://riseup.net/en/email">
         <imap
             host="mail.riseup.net"
             port="993" />
@@ -18,6 +22,17 @@
             port="587"
             starttls="true" />
     </provider>
+    <provider
+        name="Vivaldi"
+        link="https://riseup.net/en/email">
+        <imap
+            host="imap.vivaldi.net"
+            port="993" />
+        <smtp
+            host="smtp.vivaldi.net"
+            port="587"
+            starttls="true" />
+    </provider>
     <provider
         name="Gmail"
         link="https://support.google.com/mail/answer/7126229"
@@ -43,7 +58,7 @@
     </provider>
     <!-- needs subscription -->
     <provider
-        name="mailbox.org"
+        name="Mailbox.org"
         link="https://userforum-en.mailbox.org/knowledge-base/article/setup-other-e-mail-clients-manually">
         <imap
             host="imap.mailbox.org"
@@ -77,7 +92,7 @@
             starttls="false" />
     </provider>
     <provider
-        name="free.fr"
+        name="Free.fr"
         link="https://www.free.fr/assistance/597.html">
         <imap
             host="imap.free.fr"
@@ -100,7 +115,7 @@
     </provider>
     <!-- no IMAP IDLE -->
     <provider
-        name="SFR.fr"
+        name="Sfr.fr"
         link="https://assistance.sfr.fr/service-et-accessoire/sfr-mail/serveurs-messagerie-sfr.html">
         <imap
             host="imap.sfr.fr"
@@ -111,7 +126,7 @@
             starttls="false" />
     </provider>
     <provider
-        name="infomaniak"
+        name="Infomaniak"
         link="https://www.infomaniak.com/fr/support/faq/1075/configurer-une-adresse-email-configuration-logiciel-de-messagerie-parametres-courrier">
         <imap
             host="mail.infomaniak.com"
@@ -131,7 +146,7 @@
             starttls="false" />
     </provider>
     <provider
-        name="gmx.com"
+        name="Gmx.com"
         link="https://support.gmx.com/pop-imap/imap/index.html#breadcrumb_help_pop-imap_imap_server">
         <imap
             host="imap.gmx.com"
@@ -164,7 +179,7 @@
             starttls="false" />
     </provider>
     <provider
-        name="web.de"
+        name="Web.de"
         link="https://hilfe.web.de/pop-imap/imap/imap-serverdaten.html">
         <imap
             host="imap.web.de"