Main page updates

[sidorelauku]

Currently includes a lot of sections, some of those can be commented out or removed until we have content.

To update:

• [ ] Main image in header
• [ ] About the event section
• [ ] Who is speaking, replace it with 'Become a speaker' and TBA until we have content for applying.
• [ ] Event schedule - replace with a generic outline of what is expected for workshops and talk days
• [ ] Disable register section and get ticket, until we have registration open
• [ ] Our sponsors - add invite to "Become a sponsor" and remove logos. Add partners OSGEO and university of Tartu.
• [ ] Newsletter registration - we keep it if we have a newsletter
• [ ] Location - change the map to OSM and add correct location
• [ ] Update footer social icons