remove old site deployment from `gh-pages` branch

[kevinjqliu]

While browsing on google, I noticed that theres another apache iceberg website indexed.

https://apache.github.io/iceberg/blogs/

Looks like this is from the old gh-pages branch

https://github.com/apache/iceberg/tree/gh-pages

Documenting here before I remove the branch to take down the website

[kevinjqliu]

Removed the gh-pages branch, and https://apache.github.io/iceberg/ is gone

https://iceberg.apache.org/ still works