Ensure all editions examples are tested manually and update/verify tutorials

[jlouvel]

Ensure all tutorials and source code examples in user guide still work properly for all editions.

[jlouvel]

Already started by @thboileau to be completed.

Work done so far,

• all 4 editions have been tested as part of 2.2 RC3

Forking tickets for remaining work :

• tutorials : Review First Steps Tutorial : first server #884, Review First Steps Tutorial : first client #885, Review First Steps Tutorial : first application #886, Delete or review historical tutorial  #887,
• and source code examples review : User guide : Review Code Examples #888

closing, please check forked tickets.