Add a generic section on how to mount extra data into our images

We regularly get questions about how to add binaries or other files into our images at runtime.
There are a few options that we recommend and it differs per operator because not all of them support extra_volumes, but we never wrote this down in a structured fashion and picked a recommended option.

Lets add a section to the docs and spell out the main three or four options along with pros and cons and also mention what not to do.

Possible ways:

• mount OCI artifact
• copy to PV and mount that
• init container to download and copy
• gitsync

Not recommended:

• stick binary data into a ConfigMap or Secret

Repérer la section de documentation partagée appropriée et examiner comment les pages existantes de l’operator décrivent les données d’exécution et les options de volume. Ajouter une section structurée couvrant OCI artifacts, la copie vers un persistent volume, un init container et gitsync, avec leurs avantages et inconvénients, ainsi que l’avertissement de ne pas placer de données binaires dans des ConfigMaps ou des Secrets.