docs: remove old documentation source code (#400)

Signed-off-by: Leonardo Cecchi <[email protected]>

Author: leonardoce

README.md

@@ -75,58 +75,14 @@ Edit the file, and once happy remove the `draft: true` - it should now show up f
 
 ### Documentation
 
-Documentation lives [alongside the operator code](https://github.com/cloudnative-pg/cloudnative-pg),
-inside the `docs/src` folder. It is written in Markdown using mkdocs.
-
-The website contains a static copy of the HTML files generated from the
-Markdown sources, inside the `assets/documentation/$version_number` folder
-(where $version_number is a **minor** release of CloudNativePG).
-
-The `hack/import_docs.sh` script has the logic to import the files from a
-release branch, generate the HTML and save the files in the appropriate folder.
-
-Below you find instructions on how to update the docs for a new minor release
-or a patch release.
-
-#### New minor release
-
-Create a new file called `X.Y.md` (X.Y matching the minor release branch in the
-operator repo) inside the `content/docs` folder, with the following content:
-
-```markdown
----
-release:  X.Y.0
-location: /documentation/X.Y
-release_date: DD Mon Year
-release_notes: https://github.com/cloudnative-pg/cloudnative-pg/releases/tag/vX.Y.0
----
-```
-
-Then run:
-
-```console
-hack/import_docs.sh X.Y
-```
-
-This will import all the files under `assets/documentation/X.Y`. Open the
-top-level `./assets/documentation/X.Y/index.html` page with your browser and
-verify everything is OK, then add the folder to the Git repo (in a development
-branch).
-
-#### New patch release
-
-Modify the `X.Y.md` file inside `content/docs` folder by updating the version
-and the release date.
-
-Then run:
-
-```console
-hack/import_docs.sh X.Y
-```
-
-Apply all changes in the development branch and push. If you are adding a new
-patch release to the latest minor version, you will need to update the
-`current` branch (which at the moment is a copy of the folder).
+Documentation lives [alongside the operator
+code](https://github.com/cloudnative-pg/cloudnative-pg), inside the
+`docs/src` folder, is written in Markdown and compiled in a website
+using Docusaurus.
+
+The source code of the [documentation
+website](https://cloudnative-pg.io/docs) is hosted in the [docs
+repository](https://github.com/cloudnative-pg/docs).
 
 ## Publishing on the website