Validation only: power transformer/compensator compatibility with substation

[francois.lacombe]

Dear maintainers,

The power substation on nodes proposal has recently been approved on osm wiki
​https://wiki.openstreetmap.org/wiki/Proposed_features/Substation_nodes_extension

This is an "affinity proposal" which doesn't introduce nor deprecate tagging.
It's only about combination between exiting tagging, as to ease mapping substations and transformers contained inside on the same osm node.

Several validation improvement can be made, on nodes only:

• Only substation=distribution and substation=minor_distribution are valid on a node.
• Any other substation=* value than distribution and minor_distribution (anyway not valid on nodes) is incompatible with transformer=*, compensator=*, voltage:primary=*, voltage:secondary=*, voltage:tertiary=* and frequency=*.
• substation=* can be used in combination with power=tower, power=pole and man_made=street_cabinet, like on existing power=substation and pipeline=substation

On any geometry feature:

• power=transformer is incompatible with substation=*
• power=compensator is incompatible with substation=*
• transformer=* is incompatible with voltage=*
• transformer=distribution is incompatible with substation=*, and could be replaced by transformer=main

This could be processed combined to #21836

Best regards