Redirect the learn more of the OCTI demo banner to the Hub public trial page

[hervyt]

Describe the bug

At the moment, the user experience from the OCTI live demo is the following:
-I click on learn more from the banner on OCTI: https://demo.opencti.io/dashboard
-I'm asked to login on XTM Hub

We need to bring a step in the middle

-I click on learn more from the banner on OCTI
-I'm redirected to the public learn more page
-I click on start a trial and i'm asked to login on the hub

DUPLICATE OF 1477 On XTMHub