[dxf] Import/export 'DXF Export' dialog settings from/to XML

[gacarrillor]

This PR enables users to save and restore GUI settings for the DXF Export dialog, making it possible to export a number of configurations and reuse them or share them with colleagues.

Settings are exported to an XML file (see sample file content).

2024-03-18.15-39-29.mp4

Buttons to save/load to/from DXF Export settings file:

Confirmation message before overriding dialog settings with those present in the XML file:

Non-blocking confirmation of settings applied:

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Funded by the QGIS user group Switzerland.

[qgis-bot]

@gacarrillor
This pull request has been tagged as requiring documentation.

A documentation ticket will be opened at https://github.com/qgis/QGIS-Documentation when this PR is merged.

Please update the description (not the comments) with helpful description and screenshot to help the work from documentors.
Also, any commit having [needs-doc] or [Needs Documentation] in will see its message pushed to the issue, so please be as verbose as you can.

Thank you!

[DelazJ]

Not a review, just some title case suggestions

[github-actions]

🪟 Windows builds ready!

Windows builds of this PR are available for testing here. Debug symbols for this build are available here.

(Built from commit 0ed9c7d)

[DelazJ]

Not for this PR but I think we should try to improve the bottom of this dialog. Looks quite crowded imho.
And @gacarrillor can you in the meantime fix "definedBlocks" spelling on the buttons, please?

[gacarrillor]

Not for this PR but I think we should try to improve the bottom of this dialog. Looks quite crowded imho. And @gacarrillor can you in the meantime fix "definedBlocks" spelling on the buttons, please?

Thanks for your suggestions @DelazJ. All have been addressed in 3eded68

[gacarrillor]

@nirvn, thanks for your review, all your comments have been addressed in 6ca63b0

[nirvn]

@gacarrillor , thanks!

[qgis-bot]

@gacarrillor
A documentation ticket has been opened at qgis/QGIS-Documentation#8998
It is your responsibility to visit this ticket and add as much detail as possible for the documentation team to correctly document this change.
Thank you!