Mark the final state of the Jekyll effort

Before abandoning the Jekyll-based architecture (in favor of the much
faster Hugo one), this was the final state, just for the historical
record.

Merge branch 'playwright'

This topic brings in some UI testing, to build confidence not only in
the migration of the website, but also to be able to prevent (or at
least swiftly detect) regressions.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>

Merge branch 'book-fa' of bundle-fa/fa.bundle into hugo