Build modified streamline images

The official image from streamline does not currently work for the arm64
platform. As a temporary measure, the source code and docker build scripts
have been lifted from the official images and are used to build locally.

Some additional modifications are made to reduce overall image size, these
are documented in docker/README.md

docker/streamline-src/.docker/nginx/Dockerfile

@@ -0,0 +1,11 @@
+FROM  nginx:alpine3.18-slim
+
+ENV NGINXUSER=streamline
+ENV NGINXGROUP=streamline
+
+RUN set -eux; \
+    mkdir -p /var/www/html/public; \
+    adduser -g ${NGINXGROUP} -s /bin/sh -D ${NGINXUSER}; \
+    sed -i "s/user www-data/user ${NGINXUSER}/g" /etc/nginx/nginx.conf
+
+ADD .docker/nginx/default.conf /etc/nginx/conf.d/default.conf

docker/streamline-src/.docker/nginx/default.conf

@@ -0,0 +1,22 @@
+server {
+    listen 80;
+    index index.php index.html;
+    error_log  /var/log/nginx/error.log;
+    access_log /var/log/nginx/access.log;
+    server_name _;
+    root /var/www/html/public;
+
+    location / {
+        try_files $uri $uri/ /index.php?$query_string;
+    }
+
+    location ~ \.php$ {
+        try_files $uri =404;
+        fastcgi_split_path_info ^(.+\.php)(/.+)$;
+        fastcgi_pass php:9000;
+        fastcgi_index index.php;
+        include fastcgi_params;
+        fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;
+        fastcgi_param PATH_INFO $fastcgi_path_info;
+    }
+}