- [x] Have you followed the guidelines for contributing? - [x] Have you signed the [CLA](http://www.ubuntu.com/legal/contributors/)? - [x] Have you successfully run `make lint && make test`? --- This PR presents a new tutorial that covers the creation of a rock serving a static HTML file with NGINX via HTTP(s). ## **Rationale** From @medubelko: > The tutorial should be a singular, opinionated, end-to-end learning experience with a definite outcome. We’ve already achieved the latter goals in the Hello World page, but by introducing additional tutorial outcomes – for chisel, for Flask, and so forth – we’ve undermined the first two goals. The outcome is to containerise something useful, which means outside software. But the tutorial shouldn’t retread ground and cover multiple similar outcomes, making them compete with each other Additionally, the toc-tree from how-to guides has been grouped, since the old tutorials have been moved there, and there were many guides, making it hard to navigate. --- Other PRs affected by these changes: * https://github.com/canonical/rockcraft/pull/847 - modifies `/tutorial/node-app.rst` which has been moved to `how-to/rocks/pack-rocks` * https://github.com/canonical/rockcraft/pull/846 - should be closed if this is merged. New tutorial already include this. * https://github.com/canonical/rockcraft/pull/836 - changes should be made to the tutorials on the new location * https://github.com/canonical/rockcraft/pull/828 - changes should be made to the tutorials on the new location --- See [built-docs](https://canonical-ubuntu-documentation-library--855.com.readthedocs.build/rockcraft/en/855/)