Change agenda & add speakers
Add agenda
Add openEuler Summit 2021 minisite
Delete banners.
Add a blog.
Update banners.
Add news about version 20.03 LTS SP2 released.
Add 20.03 LTS SP2
Change the obs source path of videos and pictures from HK to BeiJing.
Add Bisheng JDK and secGear sites in discovery and update url
1.Add projects minisites 2.Replace banners.
Add reference links.
Update privacy policy.
1.Add sig landscape 2.Update privacy policy.
1.Update openEuler 21.03 white paper 2.add google analytics script
1.replace global font-family 2.update cve page.
Update dev day page.
Update openEuler developer day page.
Bug fix and content update.
