Install dependency tools

I forgot to add it in the last commit and this is also a good moment to use the distro composer again.

Author: vmcj

docker-contributor/Dockerfile

@@ -24,7 +24,7 @@ RUN apt-get update \
     && apt-get install --no-install-recommends --no-install-suggests -y \
     curl dumb-init autoconf automake git acl \
     gcc g++ make zip unzip mariadb-client \
-    nginx php8.3 php8.3-cli php8.3-fpm php8.3-zip \
+    nginx composer yarnpkg php8.3 php8.3-cli php8.3-fpm php8.3-zip \
     php8.3-gd php8.3-curl php8.3-mysql php8.3-intl \
     php8.3-gmp php8.3-xml php8.3-mbstring php8.3-xdebug php8.3-pcov php8.3-bcmath \
     bsdmainutils ntp lsof \
@@ -53,10 +53,6 @@ RUN groupadd -g $GID domjudge \
   && groupadd domjudge-run \
   && for id in $(seq 0 4); do useradd -d /nonexistent -g nogroup -s /bin/false "domjudge-run-$id"; done
 
-# Install composer
-RUN php -r "copy('https://getcomposer.org/installer', 'composer-setup.php');" && php composer-setup.php \
-    && mv /composer.phar /usr/local/bin/composer
-
 # Install all supported PHP versions
 RUN add-apt-repository ppa:ondrej/php -y && apt-get update && \
     for VERSION in $PHPSUPPORTED; do \