[Docs] Publish docs to gh-pages branch

[lidavidm]

#27 (comment)

[zhjwpku]

gh-pages has been populated with #237, this issue can be closed, thanks.

[kevinjqliu]

For https://cpp.iceberg.apache.org/ to work, apache infra needs to create a CNAME entry linking the gh-page

#237 (comment)