Deteremine codeowners for Sourcegraph services

Created by: daxmc99

It is hard to find codeowners at Sourcegraph. @pdubroy has created https://handbook.sourcegraph.com/departments/product-engineering/engineering/process/engineering_ownership to help address this.

Maybe we could collaborate with him to identify codeowners for some services (gitserver & symbols come up as good examples)

Colloquially, I believe that search-core owns gitserver & symbols is owned by the code intel team but there should be a table that all teams can reference.

We should also add an annotation or label to these services so that someone looking at the YAML can tell.

Lastly, there are also services like frontend which are widely shared. DevOps can be the default owners of these if not Cloud SaaS

Originally posted by @daxmc99 in https://github.com/sourcegraph/sourcegraph/issues/26911#issuecomment-999664200