[backend] refactor tools metadata schema

[scott-cohere]

1. change artifact schema to be stored as json, would look like this in payload

[
    {
        "user_id": "user-id",
        "organization_id": null,
        "id": "d972bab4-7877-47f1-892b-2c7ee34c32f3",
        "created_at": "2024-06-28T17:41:40.562919",
        "updated_at": "2024-06-28T17:41:40.562919",
        "version": 1,
        "name": "scott's assistant 3",
        "description": "",
        "preamble": "answer everything as a pirate",
        "temperature": 0.0,
        "tools": [
            "web_search"
        ],
        "tools_metadata": [
            {
                "user_id": "user-id",
                "organization_id": null,
                "id": "8234886e-280e-48eb-906b-7dedc7280a1d",
                "tool_name": "ToolName.Google_Drive",
                "artifacts": [
                    {
                        "id": "23123",
                        "name": "readme.md",
                        "type": "file"
                    },
                    {
                        "id": "123123",
                        "name": "readme",
                        "type": "folder"
                    }
                ]
            }
        ],
        "model": "command-r",
        "deployment": "Cohere Platform"
    }
]

2. Also added the tools metadata to GET agents

AI Description

This PR makes changes to the agent_tool_metadata table.

• The type column is dropped.
• The artifacts column is dropped and a new column with the same name is added, changing the data type from ARRAY(TEXT) to ARRAY(JSONB).
• The unique constraint _user_agent_tool_name_type_uc is dropped and a new one, _user_agent_tool_name_uc, is created without the type column.

The changes are also reflected in the AgentToolMetadata model and related test files.

• The type attribute is removed from the AgentToolMetadata model and related test files.
• The artifacts attribute is updated to a list of dictionaries in the AgentToolMetadata model and related test files.
• The Agent model now includes a tools_metadata attribute, which is a list of AgentToolMetadata.
• The AgentToolMetadata model is imported in the agent.py file.
• The generate:client script in package.json now uses 0.0.0.0 as the IP address instead of localhost.
• The AgentToolMetadata type in Agent.ts now includes an import statement and the tools_metadata attribute is added to the Agent type.
• The type attribute is removed from the AgentToolMetadata type in AgentToolMetadata.ts, and the artifacts attribute is updated to an array of records.
• The type attribute is removed from the CreateAgentToolMetadata type in CreateAgentToolMetadata.ts, and the artifacts attribute is updated to an array of records.
• The type attribute is made optional in the UpdateAgentToolMetadata type in UpdateAgentToolMetadata.ts, and the artifacts attribute is updated to accept null values.