Feature/add debug sql switch

Describe the MR

Adds the SQL debuging upon the presence of environment variable DEBUG_SQL.

Extra-care points?

None.

Why was this MR needed?

There is no way to switch on the debug mode for SQL (even if it's there).

Does this MR meet the acceptance criteria?

• Documentation created/updated
• Unit Tests added/updated

What are the relevant issue numbers?

N/A