Import / Ingest / Load: Consolidate resources

## About

We discovered a bunch of redundant resources.

- https://cratedb.com/docs/cloud/en/latest/cluster/import.html
- https://community.cratedb.com/t/importing-and-exporting-data-in-cratedb/1189
- https://community.cratedb.com/t/importing-data-to-cratedb-cloud-clusters/1467
- https://cratedb.com/product/features/data-import
- https://cratedb.com/blog/how-to-import-data-to-your-cratedb-cluster

Maybe there is a chance for consolidating all of them into a "usage guide"-type of document within that section.

- https://cratedb.com/docs/guide/ingest/

## References
- GH-56
- GH-224