Store table tuning statistics with globals, not routines

Currently, table tuning data is part of a class definition. Many of us are splitting routines and globals into different databases to keep the data and the code separate. This causes a problem because we have many situations where we want the same routines across multiple namespaces, but the outliers in the data are different in each of them. For example, in my specific case, we have some customers with stores in multiple locations. Because of this, if we tune the table in one namespace, it is incorrectly tuned in other namespaces and harms their performance.