Setting infraestructure for Translations (ES site) (#1906)

* set up translation infra demo

* add sample notebook for translation

* Add Spanish translations to MMM example notebook

This commit provides Spanish translations for the MMM example notebook's .po file, covering all notebook sections, explanations, and code comments. The update improves accessibility for Spanish-speaking users and ensures consistency with the original English content.

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

* Additional translation

* update contributing guide with current translation workflow

---------

Co-authored-by: Carlos Trujillo <[email protected]>
Co-authored-by: Juan Orduz <[email protected]>
Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

Author: 4 people

CONTRIBUTING.md

@@ -152,6 +152,45 @@ We recommend that your contribution complies with the following guidelines befor
     make format
     ```
 
+## Translations
+
+### For translators
+To kick off translations for the website we are going to start without any cloud-based
+collaborative translation service. This means translating will be similar to
+code contributions, people will open a PR adding the translations to the `.po` files
+inside `/locales/es/LC_MESSAGES`. PO files can be edited as raw text or with an
+editor designed for translating like [Poedit](https://poedit.net/).
+
+
+### For language coordinators/release managers
+To keep the workflow simple, we will only update the translatable sources every now and then.
+One option is to do that with every release, another option is doing it every now and then
+on a different cadence.
+
+The steps to follow to update the translatable sources are:
+
+1. Generate the updated translatable messages with Sphinx. This is similar to building
+   the website (also take more or less as long) but it generates a different kind of
+   output: `.pot` files which are a template for the language specific `.po` files
+   we'll generate later.
+
+   ```bash
+   sphinx-build docs/source docs/gettext -b gettext
+   ```
+1. Update the Spanish `.po` files
+
+   ```bash
+   sphinx-intl update -p docs/gettext -l es
+   ```
+
+### Translated build preview
+
+To build the docs in a different language:
+
+```bash
+sphinx-build docs/source docs/build -b html -D language=es
+```
+
 ## Overview of the MMM codebase
 
 Packages

docs/source/conf.py

@@ -73,6 +73,10 @@
 # The name of the Pygments (syntax highlighting) style to use.
 pygments_style = "friendly"
 
+# sphinx settings related to generation of translatable sources
+gettext_uuid = True
+gettext_compact = False
+
 # -- Extension configuration ------------------------------------------------
 
 # configure notfound extension to not add any prefix to the urls

environment.yml

@@ -29,9 +29,11 @@ dependencies:
 # Extra dependencies for lint, testing and docs build
 # docs
 - sphinx
+- sphinx-intl
 - ipython!=8.7.0
 - myst-parser
 - myst-nb
+- numpydoc
 - pydata-sphinx-theme>=0.12.0.dev0
 - sphinx-copybutton
 - sphinx-autodoc-typehints