Remove ColMap (#19544)

Now that gorp is gone, this is no longer
required.

```release-note
NONE
```

store/sqlstore/preference_store.go

@@ -18,15 +18,6 @@ type SqlPreferenceStore struct {
 
 func newSqlPreferenceStore(sqlStore *SqlStore) store.PreferenceStore {
 	s := &SqlPreferenceStore{sqlStore}
-
-	for _, db := range sqlStore.GetAllConns() {
-		table := db.AddTableWithName(model.Preference{}, "Preferences").SetKeys(false, "UserId", "Category", "Name")
-		table.ColMap("UserId").SetMaxSize(26)
-		table.ColMap("Category").SetMaxSize(32)
-		table.ColMap("Name").SetMaxSize(32)
-		table.ColMap("Value").SetMaxSize(2000)
-	}
-
 	return s
 }