Feature/add lidar depth

[AndyLi23]

I did change how the params files are handled to reduce repetition, so changes might be breaking:

• run_data = {**data, **data[run]} in data_params.py makes it possible to have params shared between runs AND params specific to runs (e.g. same robot topics, different timestamps for different runs).

• The time params format was redundant, I changed it so all that is needed to set the start & end time is:

time:
    t0: ?
    tf: ?
    relative: ?

• To toggle lidar globally or for each run: use_pointcloud: True or depth_source: 'pointcloud'

Example showing these changes:

runs: ['a', 'b']
run_env: "ROBOT"
dt: 0.16666666666666667

'a':
    time: 
        ...
    use_pointcloud: False
'b':
    time:
        ...
    use_pointcloud: True

pointcloud_data:
    path: ${BAGS_PATH}/${ROBOT}.bag
    topic: /lidar_points

Still needs official documentation & probably some cleanup, but wanted to start the merging process.