Feature - Use local state file for rover instead of remote

For local development, is it sometimes useful to deploy and test on a subscription that does not have a launchpad installed, while you still have the benefits or rover environment, variables and tools. Instead of using launchpad's storage account, state files should be stored locally.

Proposed syntax could be just omitting the ```-env``` and ```-level```:
```
rover -lz /tf/caf/examples -var-folder /tf/caf/examples/app_gateway/301-agw-v1/ -tfstate nets-102-12-1sw213s.tfstate -a plan
```
Or adding a ```-local```

```
rover -lz /tf/caf/examples -var-folder /tf/caf/examples/app_gateway/301-agw-v1/ -local -tfstate nets-102-12-1sw213s.tfstate -a plan
```