Extract name of source database from SQL scripts to feedback.sh

The name is now provided as parameter to `mysql` client,
instead of being specified in every shared SQL script
with the `USE` instruction.

I did the same in the SQL script found inline at the end
of feedback.sh.
Switch source database from `giec` to `ipcc`

No difference is found in ipcc-fact-checking
when exporting `giec` in a new branch followed by a commit,
and exporting again from `ipcc`.