Extract each file type into its own library

[vanniktech]

The XLSX export that this library provides is exactly what I was looking for. I don't need any of the file picking, the automatic support for writing it to a file. I just need the FileMapperXlsxEngine. Would you be willing to separate the library into multiple ones? Ideally, one per file type and then one big one which also provides the import/export automatic support. This way I don't need to include everything and can select individually what I want.

[vanniktech]

One thing I've noticed here:

FileMapper-KMP/filemapper/src/commonMain/kotlin/io/mamon/filemapper/engine/FileMapperXlsxEngine.kt

Line 128 in 4d6ebc5

val doubleVal = value.toDoubleOrNull()

I think it's better to change from List<List<String>> to List<List<Any>> and then check if the type if Number and then use toString() this would also support the other data types.