Migrate elasticsearch code search to Gitaly

remove (old) ruby indexer https://gitlab.com/gitlab-org/gitlab-ee/issues/6481
change (new) go indexer to use Gitaly gitlab-elasticsearch-indexer#4 (closed)

Previous issue text:

In gitlab-ee we have a feature that allows searching in Git repositories with ElasticSearch. This interacts with Git only while indexing. (?)

We have two indexers. One written in Ruby, located inside the gitlab-ee repository , and an 'experimental' one written in Go: gitlab-elasticsearch-indexer.

From a Gitaly point of view, this raises the question: which one do we migrate. The Ruby one? The Go one? Both?

Also, what is the priority of migrating the indexer(s)? I don't believe we're using them on gitlab.com, and the priority of the Gitaly migration project is to liberate gitlab.com from Git-via-NFS.

Edited Oct 23, 2020 by Nick Thomas

To upload designs, you'll need to enable LFS and have an admin enable hashed storage. More information