Since e.g. NXP-24817, there exists must-haves in deployment-fragments

Follow-up of NXP-28685, ELEMENTS-1137.
The customer has overridden in Studio the deployment fragment. This superseded the default implementation proposed since NXP-24817.

• in this case, the default fix makes WebUI non-localized
• there might exist other needs where overriding the deployment fragments might lead to non-functional features.

The request is that there exists a section "examples" in the deployment fragment part of Studio explaining e.g. that when using WebUI, you might add a line such as the ones in
https://github.com/nuxeo/nuxeo-web-ui/commit/a4cdf36a74864703b92298bad017769412eaa3e7
for each target language if wanting internationalization/localization of messages.

For other addons, there might exist must-have which should also be adequately examplified in the same spirit.

TODO

• Warning message in deployment fragment screen, before you create one

  Deployment extensions are sensitive and can conflict with Studio Designer generated configuration. Use this option with caution. [Learn more](https://doc.nuxeo.com/nxdoc/understanding-bundles-deployment/?utm_source=studio&utm_medium=deployment-extensions#deployment-fragment-preprocessor)