Add support for MongoDB environment repository in Spring Cloud Config

[apappascs]

Is your feature request related to a problem? Please describe.
Currently, Spring Cloud Config does not support MongoDB as an environment repository, which limits users who prefer MongoDB for storing configuration data.

Describe the solution you'd like
The proposed enhancement introduces support for MongoDB as an environment repository in Spring Cloud Config Server. This feature allows users to store and retrieve configuration data directly from a MongoDB database, leveraging its document-oriented storage capabilities.

Describe alternatives you've considered
Alternative solutions include using other databases that are already supported by Spring Cloud Config. However, this approach may not be ideal for users who have standardized on MongoDB, as it requires additional infrastructure and maintenance efforts.

Additional context
A Pull Request (#2390) has been submitted to introduce this feature. The PR includes the necessary code changes, tests, and documentation updates to support MongoDB as an environment repository.

Link to PR: #2390

This enhancement would benefit users who prefer MongoDB for its scalability, flexibility, and ease of use, making Spring Cloud Config more versatile and accommodating a wider range of use cases. Feedback and suggestions are welcome.