Add a "Add custom certificate" button in empty SSL Certificate List

[badkeyy]

Is your feature request related to a problem? Please describe.
When the SSL Certificate list is empty a big button "Add SSL Certificate" is displayed. However with this button one can only create a SSL Certificate using Let's encrypt and not upload a custom one. This is only possible though the dropdown menu in the top right corner of the list which can cause confusion.

Describe the solution you'd like
Introduce a new button directly within the empty SSL Certificates list interface that allows users to upload a custom SSL Certificate without needing to be of knowledge about the dropdown menu

Describe alternatives you've considered

• Document this behaviour