Onboarding Hello Tasklist

## Type of Issue
Follow-ups from https://github.com/facebookresearch/droidlet/pull/475

- [x] Write an api for navigation (equivalent of [this](https://github.com/facebookresearch/droidlet/blob/main/droidlet/lowlevel/locobot/remote/remote_locobot.py#L141)). Hello's translation[ python APIs](https://github.com/hello-robot/stretch_body/blob/master/body/stretch_body/base.py#L73) are basic.
- [x] Test 'go to x' like commands
- [x] Get camera transforms
- [x] Test point cloud
- [ ] Write an obstacle detection heuristic to make exploration work
- [ ] Clean up duplication between the hello robot and locobot agents
- [ ] Rename Locobot semantics to more generic Robot semantics and have both Locobot and Hello Robot agents inherit from/use them.
- [ ] Expand Hello's capabilities - grasping, door opening etc.

Select the type of issue:
- [ ] Bug report (to report a bug)
- [ ] Feature request (to request an additional feature)
- [x] Tracker (I am just using this as a tracker)
- [ ] Refactor request
- [ ] Documentation Ask