ORC-732: Update ORC API docs to 1.6.6 consistently

[dongjoon-hyun]

What changes were proposed in this pull request?

Like 0128f81, this PR aims to update the API doc.

Why are the changes needed?

Currently, our website is outdated and inconsistent.

• https://orc.apache.org/api/orc-core/ (ORC 1.6.5)
• https://orc.apache.org/api/orc-mapreduce/ (ORC 1.2.1)
• https://orc.apache.org/api/orc-shims/ (ORC 1.6.1)
• https://orc.apache.org/api/orc-tools/ (ORC ?)

How was this patch tested?

Manual.

$ cd site
$ git clone git@github.com:apache/orc.git -b asf-site target
$ docker build -t orc-site .
$ docker run -d -p 4000:4000 orc-site
$ open http://localhost:4000