We will be modeling future RPC implementations on an OpenAPI spec.
While this commit does not completely cohere to OpenAPI in terms
of response data, this is a good start and will allow us to cleanly
document these openapi routes in the current and future.

This commit brings in the new RPC routes:
- GET /rpc/v5/info/{pkgname}
- GET /rpc/v5/info?arg[]=pkg1&arg[]=pkg2
- POST /rpc/v5/info with JSON data `{"arg": ["pkg1", "pkg2"]}`
- GET /rpc/v5/search?arg=keywords&by=valid-by-value
- POST /rpc/v5/search with JSON data `{"by": "valid-by-value", "arg": "keywords"}`

Signed-off-by: Kevin Morris <kevr@0cost.org>