Add Now Live Branches to switch to for Leadership summit with embed for YouTube Links (Morning and Leadership Tracks)

[kjaymiller]

To make the process faster the day of we need to have YouTube embeds for both lives streams:

Each page will be defined in there own issue:

• Create Morning track PR that we can merge to change the website to the morning of the event #419
• Create an After track PR that we can merge to during the lunch changeover #420
• Create a revert track we can use to show the two youtube pages but remove the banner on the home page #421