implement generic/meta configuration from data repositories

[claeis]

Example

[CONFIGURATION]
baseConfig=ilidata:remoteBaseConfigBasketId;ilidata:otherRemoteBaseConfigBasketId;file:/path/otherBaseConfigLocalFile
org.interlis2.validator.config=ilidata:ilivalidatorConfigBasketId
ch.interlis.referenceData=ilidata:catalogBasketId;file:/path/localFile.xml

• Remote file are referenced by ilidata: and basketId
• multiple files can be referenced. It's up to the tool (e.g. ilivalidator) how it handles it. Default behaviour should be: later definitions override earlier ones.