Feature request: conditional required metadata

[billgeo]

Is your feature request related to a problem? Please describe.
Some of the metadata we want to ensure is present is conditional on other metadata. For example:

horizontal_accuracy is only required if the data is geospatial, i.e. is of geospatial_type in [point, polygon, RGB ...] and not required when in [black and white image, etc...]

There are other examples. Such as linz:language (and other metadata) is ofor the assets is only required if the data is 'published'

Describe the solution you'd like
Conditional 'required' rules based on other metadata

Find a way to add conditional 'required' metadata rules, based on other metadata.

Describe alternatives you've considered
?

Additional context
See https://confluence.linz.govt.nz/display/LIFFP/Core+and+Spatial+Metadata+Content#CoreandSpatialMetadataContent-SpatialDatasetMetadataFields