Making private some sqlstore methods (#13895)

* Making private some sqlstore methods

* Calling for create indexes on missing stores

Co-authored-by: mattermod <mattermod@users.noreply.github.com>

store/sqlstore/preference_store.go

@@ -17,7 +17,7 @@ type SqlPreferenceStore struct {
 	SqlStore
 }
 
-func NewSqlPreferenceStore(sqlStore SqlStore) store.PreferenceStore {
+func newSqlPreferenceStore(sqlStore SqlStore) store.PreferenceStore {
 	s := &SqlPreferenceStore{sqlStore}
 
 	for _, db := range sqlStore.GetAllConns() {
@@ -31,13 +31,13 @@ func NewSqlPreferenceStore(sqlStore SqlStore) store.PreferenceStore {
 	return s
 }
 
-func (s SqlPreferenceStore) CreateIndexesIfNotExists() {
+func (s SqlPreferenceStore) createIndexesIfNotExists() {
 	s.CreateIndexIfNotExists("idx_preferences_user_id", "Preferences", "UserId")
 	s.CreateIndexIfNotExists("idx_preferences_category", "Preferences", "Category")
 	s.CreateIndexIfNotExists("idx_preferences_name", "Preferences", "Name")
 }
 
-func (s SqlPreferenceStore) DeleteUnusedFeatures() {
+func (s SqlPreferenceStore) deleteUnusedFeatures() {
 	mlog.Debug("Deleting any unused pre-release features")
 
 	sql := `DELETE