Mapping should allow concatenation

[mdoering]

Mapping fields would be more powerful if the mapped source field could be added a pre- and suffix. Or even use a java formatting string with multiple fields as dynamic values.

This used to exist in the old IPT, but was removed for some reason. I found it very useful especially to create required IDs

[mike-podolskiy90]

Thanks Markus. Looks like a case of this one https://github.com/gbif/ipt/issues/1888 I also find it useful (simple case convert simple ID string to URL by prepending another string)