Save button should always be visible

User: i'm sad that there is no more "save" button on the right top in Studio (x5)

=> Move the save bar out of the editorcontainer div
=> Apply a fixed position to the save bar so that it is shown on the bottom of the screen all the time
=> Warning: make sure that there is enough space below the editorcontainer so that a user can scroll to the bottom and see the whole form ; the save bar should not hide it partially.
See screenshots for mockups and styling in comment to apply.

=> Tests to do:

• Save bar should not hide the form when scrolling to the bottom. To be done on a regular form and on the workflow graph editor also.
• Save bar should not appear in screens where it was not existing previously, like the automation chains list for instance.