Revert "Revert "Export/import passwords""

This reverts commit 4e04df2c85.

Conflicts:
	app/src/main/java/eu/faircode/email/EntityIdentity.java
	app/src/main/res/values/strings.xml

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

@@ -71,9 +71,9 @@ public class EntityAccount {
         json.put("insecure", insecure);
         json.put("port", port);
         json.put("user", user);
-        json.put("password", "");
+        json.put("password", password);
         json.put("auth_type", auth_type);
-        json.put("synchronize", false);
+        json.put("synchronize", synchronize);
         json.put("primary", primary);
         if (color != null)
             json.put("color", color);

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

@@ -89,13 +89,13 @@ public class EntityIdentity {
         json.put("insecure", insecure);
         json.put("port", port);
         json.put("user", user);
-        json.put("password", "");
+        json.put("password", password);
         json.put("auth_type", auth_type);
         json.put("primary", primary);
         if (color != null)
             json.put("color", color);
         json.put("signature", signature);
-        json.put("synchronize", false);
+        json.put("synchronize", synchronize);
         json.put("store_sent", store_sent);
         if (sent_folder != null)
             json.put("sent_folder", sent_folder);