[DRAFT] Export library to csv file

[kmturley]

Relates to #2649 and #3387

This feature allows users to export their library to csv.

Export button in Experimental settings:

Export icon in main UI:

Example csv output:

This is a prototype, if useful it could be developed into a full feature.

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Use the following Checklist if you have changed something on the Backend or Frontend:

• Tested the feature and it's working on a current and clean install.
• Tested the main App features and they are still working on a current and clean install. (Login, Install, Play, Uninstall, Move games, etc.)
• Created / Updated Tests (If necessary)
• Created / Updated documentation (If necessary)