Migrate the Beam website from Jekyll to Hugo to enable localization of the site content

Enable internationalization of the Apache Beam website to increase the reach of the project, and facilitate adoption and growth of its community.

The proposal was to do this by migrating the current Apache Beam website from Jekyll do Hugo [1]. Hugo supports internationalization out-of-the-box, making it easier both for contributors and maintainers support the internationalization effort.

The further discussion on implementation can be viewed here  [2]

[1] https://lists.apache.org/thread.html/rfab4cc1411318c3f4667bee051df68f37be11846ada877f3576c41a9%40%3Cdev.beam.apache.org%3E

[2] https://lists.apache.org/thread.html/r6b999b6d7d1f6cbb94e16bb2deed2b65098a6b14c4ac98707fe0c36a%40%3Cdev.beam.apache.org%3E