Conan Search API Endpoints

Implement the API endpoint (details below) needed in order to successfully run conan search and view available packages from the GitLab Conan registry.

This is the 5th of 6 steps to implementing the Conan API https://gitlab.com/gitlab-org/gitlab-ee/issues/8248:

1. #12567 (closed) - Skeleton API - Ping endpoint
2. #12568 (closed) - Conan authentication endpoints
3. #13345 (closed) - conan upload endpoints
4. #13350 (closed) conan install endpoints
5. #13347 (closed)conan search endpoints
6. conan info endpoints (all endpoints for conan info are implemented in previous steps)
7. #31941 (closed) conan remove endpoints

Endpoints to implement in this issue:

• GET /v1/conans/search?q=Hello - common_search

conan search makes a series of API calls to the registry (aka remote):

GET http://server:9300/v1/ping # implemented in #12567
GET http://server:9300/v1/conans/search?q=Hello