Add flag for disabled/broken/ignored packages

[AMDmi3]

Case: OpenBSD port cannot be updated to the newer version (right away), but the current version is vulnerable. Maintainer marks it as BROKEN to prevent using it. However, Repology treats it as a normal package, counting in repository vulnerable packages statistics, which is not entirely fair. We can introduce a new flag, use it for OpenBSD this way, and avoid counting vulnerabilities for such packages (also display exclamation mark in gray color, possibly add other visual indicators).