#205 Allows spreading object array elements among multiple config files.

[yruslan]

I was trying several attempts and didn't like all of them.

1. Reading configs separately as a TypeSafe Config and them combining them into a single Config object didn't work since it is not possible to add an array of objects to a config in runtime.
2. Making multiple-configs-aware Sources/Sinks/Operations deserializer complicates Pramen code a lot, and requires enormous change across the project.

So I came with a compromise solution. See #205

[github-actions]

Unit Test Coverage

File	Coverage [89.02%]	🍏
PipelineDef.scala	100%	🍏
MetaTable.scala	98.39%	🍏
ExternalChannelFactoryReflect.scala	88.54%	🍏
ConfigUtils.scala	82.59%	🍏

Total Project Coverage	79.01%	🍏

[jirifilip]

This looks like a nice and simple solution in the end, I like it :)