[Features]MinerU API Key Management

[earayu]

Proposed Changes:

1. Add MinerU API Key Configuration to Model Configuration Page: Allow administrators to configure and share MinerU API keys publicly, similar to other providers.
2. Remove MinerU API Key Configuration from Collection Settings Page: Centralize all MinerU API key management on the model configuration page.
3. Enable Free User Access to MinerU API Keys: Allow administrators to provide MinerU API keys for users to use free of charge.