Atelier Aware if a file is modified on close/ print

Summary:

• GCodeEditor::modifiedFiles to return list of modified files
• GCodeEditor::Save to allow for saving.
• New Icons for several new actions
• Ask to save if files open in gcodeview unsaved and closing.
• Ask to save if trying to print a file that was modified

Test Plan:
Open files modify them close atelier.
you should see prompts telling you to you have modified some files and test the buttons.

Open a file connect to printer modified file attempt to print before saving.
You should see A prompt asking you to save you modified file before printing (try the buttons to check their functions.

Reviewers: laysrodrigues, tcanabrava, patrickelectric, leandrosantiago

Reviewed By: laysrodrigues, tcanabrava, patrickelectric

Subscribers: leandrosantiago, Atelier: General Development

Tags: Atelier: General Development

Differential Revision: https://phabricator.kde.org/D13978