[WIP] Add visualize_dataset with http.server

[Cadene]

What this does

• Add a faster and lightweight option to visualize datasets
• Rename previous visualize_dataset.py to visualize_dataset_rerun.py

New commands

• Visualize data stored on a local machine:

local$ python lerobot/scripts/visualize_dataset.py \
    --repo-id lerobot/pusht

local$ open http://localhost:9090

• Visualize data stored on a distant machine with a local viewer:

distant$ python lerobot/scripts/visualize_dataset.py \
    --repo-id lerobot/pusht

local$ ssh -L 9090:localhost:9090 distant  # create a ssh tunnel
local$ open http://localhost:9090

• Select episodes to visualize:

python lerobot/scripts/visualize_dataset.py \
    --repo-id lerobot/pusht \
    --episode-indices 7 3 5 1 4

How it was tested

• Tried all datasets:

datasets=(
  "pusht_image"
  "xarm_lift_medium_image"
  "xarm_lift_medium_replay_image"
  "xarm_push_medium_image"
  "xarm_push_medium_replay_image"
  "aloha_sim_insertion_human_image"
  "aloha_sim_insertion_scripted_image"
  "aloha_sim_transfer_cube_human_image"
  "aloha_sim_transfer_cube_scripted_image"
  "pusht"
  "xarm_lift_medium"
  "xarm_lift_medium_replay"
  "xarm_push_medium"
  "xarm_push_medium_replay"
  "aloha_sim_insertion_human"
  "aloha_sim_insertion_scripted"
  "aloha_sim_transfer_cube_human"
  "aloha_sim_transfer_cube_scripted"
  "aloha_mobile_cabinet"
  "aloha_mobile_chair"
  "aloha_mobile_elevator"
  "aloha_mobile_shrimp"
  "aloha_mobile_wash_pan"
  "aloha_mobile_wipe_wine"
  "aloha_static_battery"
  "aloha_static_candy"
  "aloha_static_coffee"
  "aloha_static_coffee_new"
  "aloha_static_cups_open"
  "aloha_static_fork_pick_up"
  "aloha_static_pingpong_test"
  "aloha_static_pro_pencil"
  "aloha_static_screw_driver"
  "aloha_static_tape"
  "aloha_static_thread_velcro"
  "aloha_static_towel"
  "aloha_static_vinh_cup"
  "aloha_static_vinh_cup_left"
  "aloha_static_ziploc_slide"
  "umi_cup_in_the_wild"
)
for dataset in "${datasets[@]}"; do
  python lerobot/scripts/visualize_dataset.py --repo-id lerobot/${dataset} --episode-indices 0 --serve 0
done;

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This change is