Add the must-have pages for the Europa release

The goal is to capture the shape of the new docs. It is not meant to be
final, but it should be as close as possible. We only want the bare
minimum for new users that on-board with Dagger Europa. As soon as the
new europaSidebar replaces replaces the existing one, the previous docs
will still remain available - doc IDs are unique and permanent. We will
do this by simply changing the default `slug: /` to point to the Europa
Docs entrypoint, which is doc 1200.

Helpful Docusaurus link re multiple sidebars:
https://docusaurus.io/docs/sidebar/multiple-sidebars

The new pages are numbered from `1200` onwards. This is meant to reflect
the `0.2.0` Dagger version. This numbering felt more meaningful than
just continuing to increment existing numbers.

I didn't want to be "wasteful" with the digits and start at `2000`, but
that was my first instinct.

I am keen on getting this live on https://docs.dagger.io/1200/local-ci.
Anything that is not in production, is inventory. Inventory is bad.

The goal is to allow anyone that has a link to get a feel for the new
docs as soon as possible, so that we can all see how they improve in
real-time, and steer them continuously towards the desired state. We
should be aware of the timeline, and not muck about, but instead
evaluate constantly how close are we to "flipping the switch".

Remember, the best releases are those where switches are flipped (e.g.
`--europa)`. The feature will have been out there for weeks (maybe even
months), improved by talking to users and then one day realising that we
are done, and just enabling it by default. It's the same principle
behind these docs.

Signed-off-by: Gerhard Lazu <gerhard@lazu.co.uk>

.gitignore

@@ -37,3 +37,6 @@ bin/
 
 # Local environment variables
 .env
+
+# Local configuration
+.config

.markdownlint.yaml

@@ -1,7 +1,7 @@
 # Default state for all rules
 default: true
 
-# MD013/line-length - Line length
+# MD013/line-length - Allow long lines
 MD013: false
 
 # MD033 - Inline HTML. Needed for tabs in docusaurus

docs/core-concepts/1202-plan.md

@@ -0,0 +1,6 @@
+---
+slug: /1202/plan
+displayed_sidebar: europaSidebar
+---
+
+# It all starts with a plan

docs/core-concepts/1203-inputs.md

@@ -0,0 +1,6 @@
+---
+slug: /1203/inputs
+displayed_sidebar: europaSidebar
+---
+
+# Configuring inputs

docs/core-concepts/1204-secrets.md

@@ -0,0 +1,6 @@
+---
+slug: /1204/secrets
+displayed_sidebar: europaSidebar
+---
+
+# How to use secrets

docs/core-concepts/1205-container-images.md

@@ -0,0 +1,6 @@
+---
+slug: /1205/container-images
+displayed_sidebar: europaSidebar
+---
+
+# Building container images

docs/core-concepts/1206-caching.md

@@ -0,0 +1,6 @@
+---
+slug: /1206/caching
+displayed_sidebar: europaSidebar
+---
+
+# Make your builds fast

docs/core-concepts/1207-packages.md

@@ -0,0 +1,6 @@
+---
+slug: /1207/packages
+displayed_sidebar: europaSidebar
+---
+
+# Create your own package

docs/getting-started/1200-local-ci.md

@@ -0,0 +1,6 @@
+---
+slug: /1200/local-ci
+displayed_sidebar: europaSidebar
+---
+
+# Local CI setup

docs/getting-started/1201-github-actions.md

@@ -0,0 +1,6 @@
+---
+slug: /1201/github-actions
+displayed_sidebar: europaSidebar
+---
+
+# From local CI to GitHub Actions

docs/use-cases/1208-phoenix-kubernetes.md

@@ -0,0 +1,8 @@
+---
+slug: /1208/phoenix-kubernetes
+displayed_sidebar: europaSidebar
+---
+
+# Elixir/Phoenix on Kubernetes
+
+[changelog.com](https://changelog.com)

docs/use-cases/1209-docusaurus-netlify.md

@@ -0,0 +1,8 @@
+---
+slug: /1209/docusaurus-netlify
+displayed_sidebar: europaSidebar
+---
+
+# Docusaurus on Netlify
+
+[docs.dagger.io](https://docs.dagger.io)

docs/use-cases/1210-go-goreleaser.md

@@ -0,0 +1,8 @@
+---
+slug: /1210/go-goreleaser
+displayed_sidebar: europaSidebar
+---
+
+# Go with GoReleaser
+
+[github.com/dagger/dagger/releases](https://github.com/dagger/dagger/releases)

docs/use-cases/1211-go-docker-swarm.md

@@ -0,0 +1,8 @@
+---
+slug: /1211/go-docker-swarm
+displayed_sidebar: europaSidebar
+---
+
+# Go on Docker Swarm
+
+[particubes.com](https://particubes.com)

docs/use-cases/1212-svelte-vercel.md

@@ -0,0 +1,8 @@
+---
+slug: /1212/svelte-vercel
+displayed_sidebar: europaSidebar
+---
+
+# Svelte on Vercel
+
+[rawkode.dev](https://rawkode.dev)

website/sidebars.js

@@ -65,4 +65,43 @@ module.exports = {
       items: ["administrator/operator-manual"],
     },
   ],
+  europaSidebar: [
+    {
+      type: "category",
+      label: "Getting Started",
+      collapsible: false,
+      collapsed: false,
+      items: [
+        "getting-started/local-ci",
+        "getting-started/github-actions"
+      ],
+    },
+    {
+      type: "category",
+      label: "Core Concepts",
+      collapsible: false,
+      collapsed: false,
+      items: [
+        "core-concepts/plan",
+        "core-concepts/inputs",
+        "core-concepts/secrets",
+        "core-concepts/caching",
+        "core-concepts/container-images",
+        "core-concepts/packages",
+      ],
+    },
+    {
+      type: "category",
+      label: "Use Cases",
+      collapsible: false,
+      collapsed: false,
+      items: [
+        "use-cases/phoenix-kubernetes",
+        "use-cases/docusaurus-netlify",
+        "use-cases/go-goreleaser",
+        "use-cases/go-docker-swarm",
+        "use-cases/svelte-vercel",
+      ],
+    },
+  ],
 };