Make raw dialog settings saveable

[lauramurgatroyd]

Describe your changes

Closes #443
I updated standalone viewer to use this dialog.

To try it out yourself:

• install this branch of the viewer
• run 'cilviewer' on command line
• load a raw file - I recommend the head :)

to discuss

• name of the dialog is currently SaveableRawInputDialog - any suggestions?

pic of the dialog:

The pop out dialog if you press save:

Describe any testing you have performed

Consider adding example code to examples
Added unit tests to test:

• saving of settings when app is first ever opened (therefore qsettings is empty)
• saving of settings when qsettings is already populated (app has been opened before)
• loading of settings from Qsettings onto interface, by checking value in a widget

Link relevant issues

Checklist when you are ready to request a review

• I have performed a self-review of my code
• I have added docstrings in line with the guidance in the CIL developer guide
• I have implemented unit tests that cover any new or modified functionality
• CHANGELOG.md has been updated with any functionality change
• Request review from all relevant developers
• Change pull request label to 'waiting for review'

Contribution Notes

• The content of this Pull Request (the Contribution) is intentionally submitted for inclusion in CILViewer (the Work) under the terms and conditions of the Apache-2.0 License
• I confirm that the contribution does not violate any intellectual property rights of third parties

Qt contributions should follow Qt naming conventions i.e. camelCase method names.

VTK contributions should follow VTK naming conventions i.e. PascalCase method names.

[lauramurgatroyd]

Suggestions from @paskino:

• Move save button next to ok button https://doc.qt.io/qt-6/qdialogbuttonbox.html#ButtonRole-enum
• move save title and entry box to pop out dialog
• auto grey out all settings boxes once they have been loaded
• add checkbox to enable/disable editing the settings

[lauramurgatroyd]

I have made the suggested changes and updated the PR description accordingly

[lauramurgatroyd]

I believe requires #446 for action to pass

[lauramurgatroyd]

can we create a qsettings in here if one isn't passed in?

[lauramurgatroyd]

Test this case