i18n: extract, translate strings to be translated

- Extracts stings to be translated.
- Translates these strings in English and French.
- Improves some comments in the templates.
- Update the auto-changelog configuration according to the new git
  repository URL.
- Update the CHANGELOG.
- Fixes #18.

Co-Authored-by: iGor milhit <igor@milhit.ch>

README.md

@@ -125,6 +125,17 @@ postimage: "[file-name.extension]"
 postimagedescription: "[Alternate text]"
 ```
 
+## Changelog
+
+The Changelog is described in [`CHANGELOG.md`][8]. It's generated by
+[`auto-changelog`][9]. The configuration is in [`.auto-changelog`][10].
+
+To generate it, use the following command:
+
+```bash
+yarn auto-changelo
+```
+
 [1]: https://git.milhit.ch/igor/portfoligor
 [2]: https://git.milhit.ch/igor/portfoligor/issues
 [3]: https://gohugo.io/templates/homepage/#add-content-and-front-matter-to-the-homepage
@@ -132,3 +143,6 @@ postimagedescription: "[Alternate text]"
 [5]: #social-media-metadata
 [6]: https://git.milhit.ch/igor/portfoligor/src/branch/dev/LICENSE
 [7]: screenshots/theme-example.png "Screenshot of my own site using this theme"
+[8]: ./CHANGELOG.md
+[9]: https://github.com/CookPete/auto-changelog
+[10]: ./.auto-changelog