[request/session] refactor language handling: don't attempt to sync web/repo languages This decouple thing and make code easier to understand. Previous behaviour was fine w/ validation error that were translated on the server side, but isn't satisfying for notification and all. Now: * translations should be done on the ui side (see previous validation error refactoring) * consistent behaviour: each side (web/repo) is responsible to deal with its request/session of language, no weird interaction between them on this topic * drop on the way the 'session properties' api, used only for that matter. -> much simpler/cleaner/saner api The thing missing being a way for user to tell "My favorite language is xxx but I also want cw to consider my http language header)

CSS Coding Standards
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(Draft, to be continued)

:Naming: camelCase

Indentation rules
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- 2 espaces avant les propriétés

- pas d'espace avant les ":", un espace après

- 1 seul espace entre les différentes valeurs pour une même propriété


Documentation
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Please keep rules semantically linked grouped together, with a comment about
what they are for.

Recommendation
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- Try to use existing classes rather than introduce new ones

- Keep things as simple as possible while in the framework

- Think about later customization by application

- Avoid introducing a new CSS file for a few lines of CSS, at least while the
  framework doesn't include packing functionalities