Incremental build of arrow-page

[i-walker]

Enable incremental update from arrow page without rebuild the whole website.
I am not an expert in webhooks, but maybe we can use them.

The current state

We would download the webpage and map all links to the downloaded files.
Very time-consuming computation #not-multithreaded

wget -k -r -p -np https://next.arrow-kt.io/docs/

optionally there is aria2, but AFAIK it does not support recursive traversal.

Ideally

We would integrate the script/ configuration into out CI/CD to auto-build the dev-environment

• Set-up Travis