Add page for local docs preview

docs/content/docs/preview.md

@@ -0,0 +1,13 @@
+---
+title: Documentation Preview
+---
+
+The `docs:preview` task provides an opiniated solution for previewing the documentation for this project locally.
+
+It sets some expectations on the local project setup:
+
+- [`telescopium`](https://github.com/code0-tech/telescopium) is cloned in the same directory as `pictor`.
+- The directory containing this project is named `pictor`.
+
+All requirements of the `telescopium` project itself apply as well. More information about them are
+available in the [telescopium documentation](../../telescopium/preview.md).