Put up Kubecon NA ads (Sep 24)

[cjyabraham]

8 weeks prior to the start of the conference, deploy the following ads. Updated ad listing is here.

• CNCF homepage hero takeover, also see this PR and this PR
  ?utm_source=www&utm_medium=homepage&utm_campaign=kubeconna24&utm_content=hero

• CNCF hello bar; stop it showing on the homepage
  ?utm_source=www&utm_medium=subpage&utm_campaign=kubeconna24&utm_content=hello-bar

• CNCF big banner from Events infrastructure to appear on the CNCF.io homepage
  ?utm_source=www&utm_medium=all&utm_campaign=kubeconna24&utm_content=big-banner

• Kubernetes.io banner
  ?utm_source=kubernetes&utm_medium=all&utm_campaign=kubeconna24&utm_content=slim-banner

• Landscape banner
  ?utm_source=landscape&utm_medium=all&utm_campaign=kubeconna24&utm_content=slim-banner

• Jobs sidebar ad
  ?utm_source=jobs&utm_medium=homepage&utm_campaign=kubeconna24&utm_content=sidebar-banner

• Community hello bar
  ?utm_source=community&utm_medium=homepage&utm_campaign=kubeconna24&utm_content=hello-bar