Bugs #5635 & #5743 - Fixing a problem of file upload on Web browsers that are not featured with the JavaScript File API :

- adding a new system in order to decode easily the request parameters and put them automatically into a PoJo
Also :
- fixing forum subject/message form submission with file that the upload is not finished.

Don't forget to check https://github.com/Silverpeas/Silverpeas-Core/pull/535 PR.