Add descriptions to SKOS concepts about facility types

[ocorcho]

In pages 465 to 484 of the TransModel specification there are several short descriptions for most of the SKOS concepts that are used in the classification of facility types. This was not available in the corresponding XSD schemas for facility types, hence the initial SKOS codelists do not have this level of detail. However, they may be added manually.
This has very low priority.