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* Support larger impact graphs

* Handle mediumtext alteration during utf8mb4 migration

* Put back previous case to fix tests
Co-authored-by: Cédric Anne <cedric.anne@gmail.com>

 - Detect missing keys corresponding to foreign keys
 - Detect missing keys on is_* fields
 - Detect missing keys on date fields
 - Detect misnamed keys (optionnal)
 - Detect useless keys that are included in a larger key (optionnal)
 - Add missing keys
 - Drop useless keys

- Move code to a dedicated and testable class;
- Check for indexes differences;
- Check for table options differences;
- Adapt checks to DB config, DB server and DB version;
- Add parameters to adapt checks depending on already ran migrations;
- Exit with an error code when differences are found;
- Permit do do a non strict check (do not take care or fields / index orders in table);
- Call the command after each migration on test suite;
- Add tests on most relevant cases.