feat: @opensdks/cli for simplified SDK Generation

[xdotli]

Description:
We are planning to develop a new CLI tool, tentatively named @opensdks/cli, to streamline the process of generating SDKs from OpenAPI specifications. This tool will be an npm package and can be invoked using npx opensdks gen .... The idea is to follow the usability patterns of similar tools like openapi-typescript cli and create-next-app@latest.

Key Features and Workflow:

1. Input and Output:

   • The CLI will accept the URL of an OpenAPI specification as input.
   • The output will be a complete package that users can submit as a PR to our repository or use locally.

2. User Interaction:

   • The tool will provide an interactive interface - similar to npx create-next-app@latest, where users can input information as required during the generation process.
   • Alternatively, users can pass options directly in the CLI command for a non-interactive experience.

3. Ease of Use:

   • The aim is to make the SDK generation process as simple as possible, ideally boiling it down to a one-liner command.
   • Example usage: npx @opensdks/cli $OPENAPI_URL sdk-custom.

[tonyxiao]

Merging other tasks in here

• [Tools] Cli building on top of openapi-typescript to add additional functionality (extract server constant, export *, etc.)