[dev] Devcontainer tweak (#9092)

* Remove blocking steps from devcontainer setup

* Ensure postCreateCommand.sh fails

* Mount postgres db to separate dir

- Avoid ownership issues of 'dev' dir

* Bump devcontainer docs

.devcontainer/postCreateCommand.sh

@@ -1,4 +1,7 @@
 #!/bin/bash
+set -e
+
+echo "Running postCreateCommand.sh ..."
 
 # Avoiding Dubious Ownership in Dev Containers for setup commands that use git
 git config --global --add safe.directory /home/inventree
@@ -34,6 +37,3 @@ invoke dev.setup-dev
 
 # Install required frontend packages
 invoke int.frontend-install
-
-# Install playwright dependencies
-cd src/frontend && sudo npx playwright install-deps