Remove unused Dockerfiles

Signed-off-by: Ralph Sennhauser <ralph.sennhauser@gmail.com>

build/jenkins/dockerfiles/bullseye-base.Dockerfile

@@ -1,49 +0,0 @@
-FROM debian:bullseye-slim
-
-# 0 A.D. dependencies.
-ARG DEBIAN_FRONTEND=noninteractive
-ARG DEBCONF_NOWARNINGS="yes"
-RUN apt-get -qqy update && apt-get install -qqy --no-install-recommends \
-      cmake \
-      curl \
-      libboost-dev \
-      libboost-filesystem-dev \
-      libcurl4-gnutls-dev \
-      libenet-dev \
-      libfmt-dev \
-      libfreetype6-dev \
-      libgloox-dev \
-      libgnutls28-dev \
-      libgtk-3-dev \
-      libicu-dev \
-      libminiupnpc-dev \
-      libogg-dev \
-      libopenal-dev \
-      libpng-dev \
-      libsdl2-dev \
-      libsodium-dev \
-      libvorbis-dev \
-      libwxgtk3.0-gtk3-dev \
-      libxml2-dev \
-      llvm \
-      make \
-      m4 \
-      patch \
-      python3-dev \
-      python3-pip \
-      python-is-python3 \
-      subversion \
-      xz-utils \
-      zlib1g-dev \
- && apt-get clean
-
-# Install git-lfs
-RUN curl -s https://packagecloud.io/install/repositories/github/git-lfs/script.deb.sh | bash
-RUN apt-get -qqy update && apt-get install -qqy --no-install-recommends git-lfs
-RUN git lfs install --system --skip-smudge
-
-# Install rust and Cargo via rustup
-RUN curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh -s -- --default-toolchain 1.66.0 -y
-ENV PATH="${PATH}:/root/.cargo/bin"
-
-ENV SHELL=/bin/bash

build/jenkins/dockerfiles/buster-base.Dockerfile

@@ -1,52 +0,0 @@
-FROM debian:buster-slim
-
-# 0 A.D. dependencies.
-ARG DEBIAN_FRONTEND=noninteractive
-ARG DEBCONF_NOWARNINGS="yes"
-RUN apt-get -qqy update && apt-get install -qqy --no-install-recommends \
-      cmake \
-      curl \
-      libboost-dev \
-      libboost-filesystem-dev \
-      libcurl4-gnutls-dev \
-      libenet-dev \
-      libfmt-dev \
-      libfreetype6-dev \
-      libgloox-dev \
-      libgnutls28-dev \
-      libgtk-3-dev \
-      libicu-dev \
-      libminiupnpc-dev \
-      libogg-dev \
-      libopenal-dev \
-      libpng-dev \
-      libsdl2-dev \
-      libsodium-dev \
-      libvorbis-dev \
-      libwxgtk3.0-dev \
-      libxml2-dev \
-      llvm \
-      make \
-      m4 \
-      patch \
-      python3-dev \
-      python3-pip \
-      subversion \
-      xz-utils \
-      zlib1g-dev \
- && apt-get clean
-
-# From bullseye forward this is done by installing the package python-is-python3
-RUN ln -s /usr/bin/python3 /usr/bin/python
-
-# Install git-lfs
-RUN curl -s https://packagecloud.io/install/repositories/github/git-lfs/script.deb.sh | bash
-RUN apt-get -qqy update && apt-get install -qqy --no-install-recommends git-lfs
-RUN git lfs install --system --skip-smudge
-
-# Install rust and Cargo via rustup
-RUN curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh -s -- --default-toolchain 1.66.0 -y
-ENV PATH="${PATH}:/root/.cargo/bin"
-
-ENV SHELL=/bin/bash
-

build/jenkins/dockerfiles/clang9.Dockerfile

@@ -1,9 +0,0 @@
-FROM bullseye-base:latest
-
-ARG DEBIAN_FRONTEND=noninteractive
-ARG DEBCONF_NOWARNINGS="yes"
-RUN apt-get update && apt-get install -qqy llvm-9 clang-9 lld-9 libclang-9-dev --no-install-recommends
-
-ENV CC=clang-9
-ENV CXX=clang++-9
-ENV LDFLAGS="-fuse-ld=lld-9"

build/jenkins/dockerfiles/gcc8.Dockerfile

@@ -1,10 +0,0 @@
-FROM buster-base:latest
-
-ARG DEBIAN_FRONTEND=noninteractive
-ARG DEBCONF_NOWARNINGS="yes"
-RUN apt-get install -qqy gcc-8 g++-8 --no-install-recommends
-
-ENV LIBCC=gcc-8
-ENV LIBCXX=g++-8
-ENV CC=gcc-8
-ENV CXX=g++-8