Connect Mailup

1. Sign up to leadthing.dev and purchase a subscription
2. Get the leadthing.dev API key
3. Create an API key: We need the client Id and client secret
4. Provide a mailup username and password
5. Get the list id where the leads should be added to.
6. Send the Newsletter System name, the Mailup client id, the client secret, the username, the password list id and the leadthing api key to Sovendus