[Import .bar]: improve wording of pop-up information window and import report

[Import .bar]: improve wording of pop-up information window and import report

[STUDIO-1178 & STUDIO-1173] Add UTF-8 encoding in URL and changed name of HTML forms files  (use id instead of name element)

Duplicate diagram should not let the possibility to keep the same name

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Can't import (at least) xpdl (bonita 4) files when there are spaces in the path

Can't import (at least) xpdl (bonita 4) files when there are spaces in the path

Can't import (at least) xpdl (bonita 4) files when there are spaces in the path

When deleting a step, related form window should be closed in studio

- Correction on  convertion name : it was not applied on element's name