Updating devcontainer setup and related documentation

.devcontainer/post-create.sh

@@ -0,0 +1,29 @@
+#!/bin/sh
+
+# Mark the working directory as safe for use with git
+git config --global --add safe.directory $PWD
+
+# If there is no dev.js file, create it
+if [ ! -f dev.js ]; then
+  cp .devcontainer/dev.js .
+fi
+
+# Update permissions for node_modules folders
+# https://code.visualstudio.com/remote/advancedcontainers/improve-performance#_use-a-targeted-named-volume
+if [ -d node_modules ]; then
+  sudo chown $(id -u):$(id -g) node_modules
+fi
+
+if [ -d client/node_modules ]; then
+  sudo chown $(id -u):$(id -g) client/node_modules
+fi
+
+# Install packages for the server
+if [ -f package.json ]; then
+    npm ci
+fi
+
+# Install packages and build the client
+if [ -f client/package.json ]; then
+    (cd client; npm ci; npm run generate)
+fi