Change the user experience when creating an organisation

[Pauline0504]

As it is now:

• Click on "create an organization"
• Send to "user sign up"
• Then send back to landing page (cf picture 1)

Would like to improve for:

• Click on "create an organization"
• Send to "user sign up"
• Then Send to a "Thank you for joining" page - "Welcome! We are happy to have you with us." and with a message below "Maybe you have an organization, a job or an event to promote? Click on the link below, you're just a few tiny steps away!" with a link included toward -> create an organisation!"