Reorganize documentation for new website (#213)

This PR should be merged after the new website is deployed.

- [x] Rename files
- [x] Add front matter section to all `.md` files in the book (necessary for Zola)
- [x] Change all internal links to use Zola's linking system that checks broken links
- [x] Some updates to documentation contents and organization

Co-authored-by: Alex Auvolat <alex@adnab.me>
Reviewed-on: https://git.deuxfleurs.fr/Deuxfleurs/garage/pulls/213
Co-authored-by: Alex <alex@adnab.me>
Co-committed-by: Alex <alex@adnab.me>

1 files changed, 13 insertions, 0 deletions

diff --git a/doc/book/working-documents/_index.md b/doc/book/working-documents/_index.md
new file mode 100644
index 00000000..9871d206
--- /dev/null
+++ b/doc/book/working-documents/_index.md
@@ -0,0 +1,13 @@
++++
+title = "Working Documents"
+weight = 7
+sort_by = "weight"
+template = "documentation.html"
++++
+
+Working documents are documents that reflect the fact that Garage is a software that evolves quickly.
+They are a way to communicate our ideas, our changes, and so on before or while we are implementing them in Garage.
+If you like to live on the edge, it could also serve as a documentation of our next features to be released.
+
+Ideally, once the feature/patch has been merged, the working document should serve as a source to 
+update the rest of the documentation and then be removed.