feat: add postgresql toolkit

Author: mudssky

scripts/pwsh/devops/Postgres-Toolkit.Help.md

@@ -0,0 +1,14 @@
+# Postgres Toolkit Help
+
+## Commands
+
+- `backup`
+- `restore`
+- `import-csv`
+- `install-tools`
+
+## Examples
+
+```powershell
+./Postgres-Toolkit.ps1 backup --database app --output ./app.dump --format custom
+```