v2023: documentation-builder: Drop as it is now unused

We used to build our docs with hotdoc and that required some special bits.

We're still using Pandoc and LaTeX which are annoyingly special as well, but definitely less unique.

We moved the website hosting our documentation to Hugo a long time ago, which this image does not even ship, and the last usage for generating PDF has been dropped a few months ago: docs/apertis-website!508 (merged)

See also !300 (merged)

documentation-builder/Dockerfile

-FROM debian:buster-slim
-ENV LC_ALL C.UTF-8
-ARG DEBIAN_FRONTEND=noninteractive
-
-# Always install procps in case the docker file gets used in jenkins
-RUN apt update && apt-get install  --no-install-recommends -y procps
-
-# Bits needed to upload the documentation
-RUN apt-get update  && \
-    apt-get install --no-install-recommends -y rsync \
-                                               libnss-wrapper \
-                                               openssh-client
-
-# Bits needed to run the build
-RUN apt-get update  && \
-    apt-get install --no-install-recommends -y python3-pip \
-                                               python3-setuptools \
-                                               python3-wheel \
-                                               build-essential \
-                                               python3-dev \
-                                               libxml2-dev \
-                                               libxslt1-dev \
-                                               libglib2.0-dev \
-                                               pkg-config \
-                                               build-essential \
-                                               cmake \
-                                               libyaml-dev
-
-# Bits needed for pdf generation; install recommends here to ensure the latex
-# installation is complete
-RUN apt-get update  && \
-    apt-get install -y libjson-glib-dev \
-                       fonts-noto \
-                       fonts-freefont-ttf \
-                       pandoc \
-                       python \
-                       python-lxml \
-                       python3-pandocfilters \
-                       texlive-xetex \
-                       librsvg2-bin
-
-RUN pip3 install hotdoc
-
-# Bits needed for website generation
-RUN apt-get update  && \
-    apt-get install -y apt-transport-https \
-                       devscripts
-
-RUN mkdir -p /etc/apt/sources.list.d
-COPY apertis-infrastructure.list /etc/apt/sources.list.d/
-
-RUN mkdir -p /etc/apt/trusted.gpg.d/
-COPY collabora-obs-archive-keyring.gpg /etc/apt/trusted.gpg.d/
-
-# Defer libnss-unknown package installation to the end to avoid possible UID/GID problems
-RUN apt-get update  && \
-    apt-get install --no-install-recommends -y libnss-unknown