Implement CLI for ingested codeowners
Created by: eseliger
'src codeowners' is a tool that manages ingested code ownership data in a Sourcegraph instance.
Usage:
src codeowners command [command options]
The commands are:
get returns the codeowners file for a repository, if exists
create create a codeowners file
update update a codeowners file
delete delete a codeowners file
Use "src codeowners [command] -h" for more information about a command.
Requires https://github.com/sourcegraph/sourcegraph/pull/48584.
Closes https://github.com/sourcegraph/sourcegraph/issues/47823.
Test plan
Verified with the new backend endpoints.