Localize service error messages

app/src/main/java/eu/faircode/email/EmailService.java

@@ -340,7 +340,7 @@ public class EmailService implements AutoCloseable {
         } catch (MailConnectException ex) {
             if (ConnectionHelper.vpnActive(context)) {
                 MailConnectException mex = new MailConnectException(new SocketConnectException(
-                        "The might be caused by the VPN in use",
+                        context.getString(R.string.title_service_vpn),
                         new Exception(),
                         ex.getHost(),
                         ex.getPort(),
@@ -351,7 +351,7 @@ public class EmailService implements AutoCloseable {
                 throw ex;
         } catch (MessagingException ex) {
             if (port == 995 && !("pop3".equals(protocol) || "pop3s".equals(protocol)))
-                throw new MessagingException("Please double check the port number", ex);
+                throw new MessagingException(context.getString(R.string.title_service_port), ex);
             else
                 throw ex;
         }

app/src/main/res/values/strings.xml

@@ -589,6 +589,8 @@
     <string name="title_oauth_support">OAuth is not supported</string>
     <string name="title_review">Review</string>
     <string name="title_hint_alias">Long press for options, like copy to create alias identities</string>
+    <string name="title_service_vpn">This might be caused by the VPN that is being used</string>
+    <string name="title_service_port">Please double check the port number</string>
 
     <string name="title_advanced_browse">Browse messages on the server</string>
     <string name="title_advanced_expand_read">Mark messages read on expanding</string>