Add links to previous and next page in footer

Several sections of the docs, such as the installation part, the whole
user guide, or the different steps of running the VLAB, are easy to read
in a continuous fashion: start with the first page, follow-up with the
next ones.

To help with navigation in such cases, add links to the previous and
following pages of the documentation to the footer.

Link: https://squidfunk.github.io/mkdocs-material/setup/setting-up-the-footer/
Signed-off-by: Quentin Monnet <[email protected]>

mkdocs.yml

@@ -25,6 +25,7 @@ theme:
     - navigation.expand
     - toc.follow
     - navigation.top
+    - navigation.footer
     - search.suggest
     - search.highlight
     - search.share