[enhancement] Update rover flags to be more consistent with Terraform

RIght now Rover is essentially a helper/wrapper for terraform that manages things to work better with the launchpad. However, rover uses a completely unique syntax in order to interact with it.

I think it would speed adoption if rover use was in parity with terraform use, at least the key features.

Example: don't require `-lz` or `-a` in order to select a landingzone and action (especially as its just essentially just a project). Allow [dir] to be specified if desired, or just run off the current directory if not (you can read full path and get the "landingzone" name anyway).

These little differences trip things up a lot. Look at the following, especially if Ive already browsed into the project folder in question:

```
terraform plan

# vs

rover -a plan -lz /tf/caf/full/path/

# but image this

rover plan
```

This would make rover a bit more "terragrunt-like", but I dont thinkj thats a bad thing.

Start by locating Rover's CLI entry point and the handling for the -a, -lz, and directory arguments, then compare those behaviors with the Terraform command examples in the issue. Done means Rover can run commands such as `rover plan` from the current or specified directory while preserving the needed landing zone and action behavior.

Written by the indexing model from the issue text.