Option to apply dimension/spacing changes to all/selected layers

[chili-chiu]

[nice to have feature]
Currently users can edit dimension/spacing for each layer.
In cases where multiple layers exist and share the same dimension/spacing (e.g. multi-channel, other layer types that represent the analysis of the image layer), changing them one by one can be tedious.

Providing an option to apply dimension/spacing changes to all/selected layers could make it easier.

[andy-sweet]

This should always occur for dimension names, since this plugin is actually modifying the viewer axis labels (i.e. we can't easily do anything else). We should probably make this occur for dimension types for consistency.

But scale/spacing is one that is layer specific, so we may want an option to control that.