Is your feature request related to a problem? Please describe.
At the moment, downsampling is disabled in default panel settings, and must be enabled in each panel individually during the app preconfiguration.

Describe the solution you'd like
Allow the user to set (and examine) a variety of global options which affect the way in which the various panel constructors initialize the default settings.
Essentially a wrapper around ?options.
In addition to downsampling, this could also be used to set a different default value for other fields, e.g.:

• .organizationHeight
• .organizationWidth
• .selectParamBoxOpen
• .dataParamBoxOpen
• .colorByDefaultColor
• .selectColor
• .selectTransAlpha
• .visualParamBoxOpen
• .contourAdd
• .contourColor
• .plotPointSize
• .plotPointAlpha
• .plotPointDownsample
• .plotPointSampleRes
• .plotFontSize
• .plotLegendPosition

Essentially, any field that does not depend on the contents of se.

Describe alternatives you've considered
Modes can address this to some extent.

Additional context
n/a