MW372 Provide mod_security

[abrahammartin]

mod_security needs a configuration. Not clear if it can be usefully added either just with a default configuration or with an administrator-modifiable one, or if it will only be useful with a custom one. If the latter, many of our users will be unable to set it up.

Just adding the Core Rule Set: https://modsecurity.org/crs/ might be a workable plan.