Deprecate unused functions _tracker_myrecent_access and _tracker_user_access

When all hook_menu implementations were removed → , internal helper functions _tracker_myrecent_access() and _tracker_user_access() became unnecessary.

The first, _tracker_myrecent_access() was replaced by declarations in tracker.router.yml (tracker.users_recent_content), tracker.services.yml (access_check.tracker.view_own), and src/Access/ViewOwnTrackerAccessCheck.php (class ViewOwnTrackerAccessCheck).

While _tracker_user_access() was replaced by a declaration in tracker.router.yml (tracker.user_tab).

Nothing in D8 invokes these functions. There is a stale reference to _tracker_myrecent_access in modules/migrate_drupal/src/Tests/Table/d7/MenuRouter.php.