Documentation: Improve docs for ctk load table

[amotl]

Just a small thing that it may be worth mentioning in the docs, the schema translation part takes the name of the MongoDB collection for the CREATE TABLE statement but the data load part takes the table name from the CRATEDB_SQLALCHEMY_URL so these 2 have to match for ctk load table to work.

Originally posted by @hlcianfagna in #216 (review)

[amotl]

Hi Hernan. Thanks for your suggestion. I am sure there are anomalies, but I can't spot them, probably because of operational blindness, and your description doesn't tell me anything where to apply an improvement, and what, at least not enough to make it actionable for me.

I know that migr8 splits the procedure into two phases, and that ctk load table bundles it. In this spirit, I don't know where to discriminate, and/or improve the documentation. Apologies.

Can I humbly ask you to submit a corresponding suggestion how and where to improve the documentation, either by commenting on the patch GH-216, or by submitting a separate one? Thanks a stack!