Conan Search API Endpoints

What does this MR do?

This implements the endpoints required to perform conan search commands using the GitLab Conan package registry. This is behind a feature flag until the entire Conan MVC is complete, so it does not require a changelog at this time.

This adds the endpoint /v1/conans/search?q=Hello to the conan api. This endpoint is requested from the Conan CLI when a user is searching for conan packages. The path and params are defined by the conan package manager. Conan package names are called "recipes" and look like package-name/version@plus+separated+project+path/channel, so an example might be: my-package/1.0.0@gitlab-org+gitlab/beta. Users can search for packages providing the query param q. The search should search against the first part of the recipe, the package-name, and if a * is included, it acts as a wildcard matching anything beginning with the user's query. If a user enters an entire recipe into the query, only that package should be returned.

Documentation is being handled in a separate MR !16349 (merged)

Screenshots

Does this MR meet the acceptance criteria?

Conformity

• Changelog entry
• Documentation created/updated or follow-up review issue created
• Code review guidelines
• Merge request performance guidelines
• Style guides
• Database guides
• Separation of EE specific content

Performance and Testing

• Review and add/update tests for this feature/bug. Consider all test levels. See the Test Planning Process.
• Tested in all supported browsers

Security

If this MR contains changes to processing or storing of credentials or tokens, authorization and authentication methods and other items described in the security review guidelines:

• Label as security and @ mention @gitlab-com/gl-security/appsec
• The MR includes necessary changes to maintain consistency between UI, API, email, or other methods
• Security reports checked/validated by a reviewer from the AppSec team

Related #13347 (closed), #8248 (closed)