Previously the Puma low-level error handler was specified in three
different places (Cloud Native GitLab, Omnibus GitLab, GitLab
Development Kit). Any time a change was needed we would have to update
three different files. We can simplify this by putting in a central
class that each of the configuration files can use.

Relates to https://gitlab.com/gitlab-org/gitlab/-/issues/426135

Changelog: changed