feat(docs): connection ui documentation

[AndrewKaranja]

This PR introduces connection files for the following providers:

• Make - Implements API Key and domain-based connection setup for the Make platform.
• Metabase - Configures API Key authentication for Metabase with domain-specific settings.
• Mailgun - Adds support for Mailgun with API Key-based authentication and domain configurations.
• Manatal - Enables API Key-based connection for Manatal with user and role-specific configurations.
• Medallia - Implements OAuth 2.0 Client Credentials flow for Medallia.
• Mindbody - Adds API Key and domain-based connection for Mindbody.
• Next Cloud OCS - Configures Basic authentication for Next Cloud OCS.
• OpenAI - Enables OpenAI connection using API Key for accessing productivity and developer tools.

[linear]

EXT-272 Connect UI Documentation (6 of 10)