GraphQL API: Filter runners by search text

Summary

In !61174 (merged) we introduced a way for users to find runners using the GraphQL API, we should extend this API with free-text search.

Description

The HAML implementation of the runners allows users to find runners by partial matching description:

Free text search

This should be ported to the new GraphQL runner filters.

Variable scope

We can port have port only the description search, we could also add some other fields to the text search, like the short token, and IP. 🤔