Sedona new website is online

[Jia Yu <ji...@apache.org>]

Hi folks,

I just refactored the sedona website: http://sedona.apache.org/

I eventually choose to still use mkdocs to manage our documentation
website. Since we already use mkdocs before, re-build everything using
Jekyll requires too much work.

The documentation source code is still in "docs" and "docs-override". You
can still build it using "mkdocs serve" and make sure you have "material"
theme installed:
https://squidfunk.github.io/mkdocs-material/getting-started/

Thanks,
Jia