Add option to save settings per-workspace

[Katsute]

Relevant Issues

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• Closes Workspace Specific Configuration #381

Changes Made

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• Add typecheck to build
• Adds option to save background settings to workspace
• Install uses workspace with global fallback
• Background menu uses workspace without fallback
• Background menu specifies global value
• Default is returned in all cases

Release Notes

This updates the configuration menu to allow workspace specific settings; to use workspace, toggle the Setting Scope in the more options menu. Does not automatically update the background on workspace switch, the Auto Install option needs to also be turned on.

Setting this to workspace will always use the workspace configuration, it does not fallback to global settings.

[Katsute]

When using workspace, menu should get workspace or default, not global. Menu should say the global value alongside the workspace one.

[Katsute]

Fallback causes unexpected behavior with array settings, setting any one will not fallback the rest of the values which is counter intuitive.

Workspace option will only pull in workspace.

[kdevbot]

Approved by @Katsute