Implement new create() methods for the Agent(), Environment(), Orchestrator(), Tool() classes

[richardblythman]

Depends on #43.
Partially depends on #41 and #44.

Implement new create() methods for the Agent(), Environment(), Orchestrator(), Tool() classes for downloading and installing a module to a node. These new methods will use the corresponding new create_* methods of the node client (from #43).

Here is an example of how it will be used:

from naptha_sdk.agent import Agent

agent_deployment = {
    "module": {"name": "simple_chat_agent"},
    "worker_node_url": "https://node.naptha.ai"
}

agent = Agent()

response = agent.create(agent_deployment)

response = await agent.call_agent_func(
    tool_name="chat", 
    tool_input_data="What is an AI agent?", 
)