Add CSV importer examples

[littleli]

CSV files are the most common format that you can receive out of traditional storage system like RDBMS and DWH solutions. To my untrained beginner eyes there is a plenty of additional settings I don't know how to use to produce CSV exports that can be easily imported to ArcadeDB.

It seems there are settings to import edges, vertices and documents separately. My suggestion is to have an example with a single import file and another example with multiple import files to demonstrate the usage of the importer settings.

[Caveats]

I'm looking at just this. It's easy enough to get it into JSON - but the JSON importer GUI seems to suffer from the SWOD (spinning wheel of death). A better example of the schema or JSON / CSV format would be great. Currently picking over this:

https://github.com/ArcadeData/arcadedb-datasets/raw/main/orientdb/OpenBeer.gz

But it would be much better to have some CSV template to wade through.