[BugFix] File save dialog now requires a valid filename

[waaake]

Validating the filename to ensure that the file does not gets saved with just the extension

Description

• Added a Validation to the file and template save process to ensure we have a valid filename to save to and not just the extension in the saved filename.

Features list

Implementation remarks

• The validation process involves showing up a dialog box prompting user to provide a correct filename to save. This dialog box is recurring till the time a valid filename is entered for saving the file.

[waaake]

Thanks @yann-lty for the wonderful suggestions on the PR, this is working as expected with function and reused implementation of MessageDialog as a warning.

The only annoyance that I get is of this error at the moment,
Created Graphical Object was not placed in the Graphics Scene
With myself trying to pass a parent which comes from the main.qml (parent.parent) or (root.parent) instead of root still somehow causes this to be raised.