docs: starter pack (#417)

Introducing Canonical starter pack into pebble docs.

.gitignore

@@ -7,5 +7,5 @@ cmd/VERSION
 .idea
 .vscode
 /pebble
-
+.tox/
 dist/

HACKING.md

@@ -202,6 +202,22 @@ ok      github.com/canonical/pebble/cmd/pebble  0.165s
 ...
 ```
 
+## Docs
+
+We use [`sphinx`](https://www.sphinx-doc.org/en/master/) to build the docs with styles preconfigured by the [Canonical Documentation Starter Pack](https://github.com/canonical/sphinx-docs-starter-pack).
+
+### Building the Docs
+
+To build the docs, run `tox` under the `docs/` folder.
+
+### Pulling in the Latest Style Changes and Dependencies
+
+To pull in the latest style and dependencies from the starter pack, clone the [Canonical Documentation Starter Pack repository](https://github.com/canonical/sphinx-docs-starter-pack), and follow the README there. TL;DR:
+
+- Copy the content into the `docs/` folder.
+- Remove unnecessary files (like Makefile, cheat sheets, etc.)
+- Under the `docs/` folder, run `python3 build_requirements.py`. This generates the latest `requirements.txt` under the `.sphinx/` folder.
+- Under the `docs/` folder, run `tox -e docs-dep` to compile a pinned requirements file for tox environments.
 
 ## Creating a release
 

docs/.gitignore

@@ -0,0 +1,12 @@
+/*env*/
+.sphinx/venv/
+.sphinx/warnings.txt
+.sphinx/.wordlist.dic
+.sphinx/.doctrees/
+.sphinx/node_modules/
+package*.json
+_build
+.DS_Store
+__pycache__
+.idea/
+.vscode/

docs/.readthedocs.yaml

@@ -0,0 +1,32 @@
+# .readthedocs.yaml
+# Read the Docs configuration file
+# See https://docs.readthedocs.io/en/stable/config-file/v2.html for details
+
+# Required
+version: 2
+
+# Set the version of Python and other tools you might need
+build:
+  os: ubuntu-22.04
+  tools:
+    python: "3.11"
+  jobs:
+    post_checkout:
+      - cd docs && python3 .sphinx/build_requirements.py
+  apt_packages:
+    - distro-info
+
+# Build documentation in the docs/ directory with Sphinx
+sphinx:
+  builder: dirhtml
+  configuration: docs/conf.py
+  fail_on_warning: true
+
+# If using Sphinx, optionally build your docs in additional formats such as PDF
+formats:
+   - pdf
+
+# Optionally declare the Python requirements required to build your docs
+python:
+   install:
+   - requirements: docs/.sphinx/requirements.txt