Set higher default ulimit in Docker Compose/K8s deployments

Created by: dadlerj

Reported by https://app.hubspot.com/contacts/2762526/company/947819054

They are deployed using Docker Compose

We had a user receive the following error from the following search “lang:typescript type:commit after:"1 week ago"”

1 error occurred: 

 commit search failed: failed to search commit log <REPO REDACTED>@: git command [git log --no-prefix --max-count=31 --extended-regexp --regexp-ignore-case --since=1 week ago -z --no-abbrev-commit --format=oneline --no-color --source --no-patch --no-merges --extended-regexp --max-count=500 --] failed (output: ""): open /dev/null: too many open files (stderr: "")

They can reproduce reliably using structured search, and users have seen it intermittently since then.

This issue coincides with a lot of new users coming on to Sourcegraph at the company.

We are debugging and helping them set higher ulimit, but we should update defaults to prevent this.