- external resources can be provided through the grid options, but these options are sometime deep copied and that might have the side effect of losing the singleton ref of the instantiate services/resources, instead we can simply keep these singleton refs before any grid options merge can happen and that is in the constructor before the grid initializes and before the grid options are merged and sometime deep copied with global options

- add `registerExternalResources` method to push extra external resources
- rename grid option (deprecate previous name) `registerExternalResources` because it's confusing with the method name and an option shouldn't be named with something that sound like an execution
- add `resetExternalResources()` method but that is mostly useful for unit tests