Grouping transfer-related build config parameters into a single object

[VillePihlava]

Is your feature request related to a problem? Please describe.

Transfer-related parameters in the build-config.json file are located under the root object, netexDefaults, gtfsDefaults and so on. Grouping them under a single object called, for example, transferParameters would make the configuration more understandable.

For example, at least the locations of these parameters could be considered:

• maxTransferDuration
• blockBasedInterlining
• discardMinTransferTimes
• stationTransferPreference
• noTransfersOnIsolatedStops
• transferRequests
• transferParametersForMode