Drop NOKOGIRI_USE_SYSTEM_LIBRARIES=1 on nokogiri installation
Why
Compacts the registry.gitlab.com/gitlab-org/gitlab-docs:base
image size.
Drops the maintenance cost of nokogiri library from this repo.
What
This MR uses the recommended installation method of Nokogiri and with it this MR removes libxml2, libxml2-dev, libxslt, libxslt-dev packages from the base image. Note: libxml2/libxml2-dev are implicitly required by libxslt/libxslt-dev.
Closes #846 (closed)
Edited by Takuya Noguchi