feat: add workspace-level max active requests limit

### Self Checks

- [x] I have read the [Contributing Guide](https://github.com/langgenius/dify/blob/main/CONTRIBUTING.md) and [Language Policy](https://github.com/langgenius/dify/issues/1542).
- [x] I have searched for existing issues [search for existing issues](https://github.com/langgenius/dify/issues), including closed ones.
- [x] I confirm that I am using English to submit this report, otherwise it will be closed.
- [x] Please do not modify this template :) and fill in all the required fields.

### 1. Is this request related to a challenge you're experiencing? Tell me about your story.

I expect to add a workspace-level control to manage the total resource consumption per space, in order to regulate machine resource usage.

### 2. Additional context or comments

_No response_

### 3. Can you help us with this feature?

- [x] I am interested in contributing to this feature.