feat(robots): consolidates bi SO setups

[imstevenpmwork]

Type / Scope

• Type: Feature | Chore
• Scope: Robots & Teleoperators

Summary / Motivation

• Now the Bi SO robot definition is able to be either SO100 or SO101 setups without the need of new code
• This led to further simplify the single SO

Related issues

• Fixes / Closes: N/A
• Related: Builds on top of feat(robots): consolidate SO arms implementation #2763 to ultimately simplify feat(robots): add xlerobot and composite teleop <leaders+gamepad> definitions #2484

What changed

• Bi SO implementation now uses the SO base class (which works for both SO100 & SO101)
• Headers, Documentation & BiSO robot code to have a base class.
• Re-calibration is required
• SO10X classes deleted, but alias added to prevent breaking changes

How was this tested

• pytest -vv tests/
• Did a HW teleop & record test in both a single pair setup and a double pair setup

Checklist (required before merge)

• Linting/formatting run (pre-commit run -a)
• All tests pass locally (pytest)
• Documentation updated
• CI is green

Reviewer notes

• Now all calibration files will be under the same directory. Example:

(base) λ › pwd
/<user>/.cache/huggingface/lerobot/calibration/robots/so_follower
(base) λ › ls 
bimanual_follower_left.json  bimanual_follower_right.json black.json

[HuggingFaceDocBuilderDev]

The docs for this PR live here. All of your documentation changes will be reflected on that endpoint. The docs are available until 30 days after the last update.

[CarolinePascal]

LGTM ! Let's add some docs now ;)