docs: Add note on running Docker without sudo in installation guides (#721)

Author: you-n-g

README.md

@@ -73,6 +73,7 @@ You can try above demos by running the following command:
 
 ### 🐳 Docker installation.
 Users must ensure Docker is installed before attempting most scenarios. Please refer to the [official 🐳Docker page](https://docs.docker.com/engine/install/) for installation instructions.
+Ensure the current user can run Docker commands **without using sudo**. You can verify this by executing `docker run hello-world`.
 
 ### 🐍 Create a Conda Environment
 - Create a new conda environment with Python (3.10 and 3.11 are well-tested in our CI):

docs/installation_and_configuration.rst

@@ -11,6 +11,7 @@ Installation
 - for dev users: `See development <development.html>`_
 
 **Install Docker**: RDAgent is designed for research and development, acting like a human researcher and developer. It can write and run code in various environments, primarily using Docker for code execution. This keeps the remaining dependencies simple. Users must ensure Docker is installed before attempting most scenarios. Please refer to the `official 🐳Docker page <https://docs.docker.com/engine/install/>`_ for installation instructions.
+Ensure the current user can run Docker commands **without using sudo**. You can verify this by executing `docker run hello-world`.
 
 LiteLLM Backend Configuration
 =============================