GitLab

* feat(fragment) Remove modal widget into fragment editor

closes [BS-19121](https://bonitasoft.atlassian.net/browse/BS-19121)

* fix cursor on modalContainer widget in fragment editor

Due to editor layout implementation using flexbox, some fine tuning needed to be done for safari

Closes [BS-16105](https://bonitasoft.atlassian.net/browse/BS-16105)

This allows the editor panels to be displayed and showing a loading
message while the artifact is renderred inside whiteboard.

Closes [BS-15887](https://bonitasoft.atlassian.net/browse/BS-15887)

* refactor(editor-layout) Use flexbox instead of absolute position
* refactor(bottom-panel) Use angular-resizable to resize panel

Create a file viewer widget that allows to view Bonita document
or files via a URL. A preview can be displayed under the file name
and cilc on a PDF or image file opens a fullscreen overlay
thanks to fancybo jquery plugin.

Closes [BS-14978](https://bonitasoft.atlassian.net/browse/BS-14978)
Closes [BS-14979](https://bonitasoft.atlassian.net/browse/BS-14979)
Closes [BS-14980](https://bonitasoft.atlassian.net/browse/BS-14980)
Closes [BS-14983](https://bonitasoft.atlassian.net/browse/BS-14983)
Closes [BS-14984](https://bonitasoft.atlassian.net/browse/BS-14984)