Setting for OpenX-specific implementations

[devjwsong]

• Added some OpenAI models hardcoded for setting OpenAIModule.
• Added the prompt format and prompt formatting function.
• Added the description, action spaces, and action exclusiveness definitions of one of datasets in OpenX (berkeley_autolab_ur5)
  • DESCRIPTIONS has dataset name => environment name (or any text to identify it) => description sentences.
  • ACTION_SPACES has dataset name => environment name (or any text to identify it) => action index: action definition pairs.
    • If the action is discrete, the action definition has description, and another key-value pairs which represents the index and value.
    • If the action is continuous, the action definition has description, minimum value, and maximum value.
  • ACTION_EXCLUSIVENESS: has dataset name => environment name (or any text to identify it) => boolean value.
    • If each action is mutually exclusive, that means the model should perform only one action at a time.