Add import.sh script + datasets clean up

[MaBeuLux88]

Add an import.sh with a few options:

• can start a MongoDB instance in a docker container.
• can point to any MongoDB server (given an URI).
• can insert only the smallest datasets for live demos or all of them.

Also did some cleaning in the datasets list. Some links where 404 NOT FOUND and another one was a complete mess (Northwind) as the CSV files where malformed, the fields and values were completely mixed during the import process - the dataset didn't make any sense.

[ozlerhakan]

thank you @MaBeuLux88 for your PR

[ozlerhakan]

merged!