update: docs for qewn2.5vl, x0, x0.5, add energon instal

Author: Hchnr

examples/robobrain_x0/README.md

@@ -22,6 +22,7 @@ Install FlagScale and robotics dependencies:
 cd FlagScale/
 pip install . --verbose
 pip install -r requirements/train/robotics/requirements.txt
+pip install git+https://github.com/NVIDIA/Megatron-Energon.git@ab40226
 ```
 
 Install Megatron:

examples/robobrain_x0_5/README.md

@@ -22,6 +22,7 @@ Install FlagScale and robotics dependencies:
 cd FlagScale/
 pip install . --verbose
 pip install -r requirements/train/robotics/requirements.txt
+pip install git+https://github.com/NVIDIA/Megatron-Energon.git@ab40226
 ```
 
 ## Training