Migrate all text filter parameters to regex matching

[markuslf]

Goal

Replace all simple string/substring/startswith filter parameters with Python regular expression matching across all plugins. This gives admins more flexibility without requiring separate --ignore-pattern and --ignore-regex parameters.

Background

Some plugins offer both --ignore-pattern (substring match) and --ignore-regex (regex match) for the same purpose, or use substring/startswith matching for filters like --ignore, --command, --username, etc. Regular expressions are a superset of simple strings: httpd as a regex still matches "httpd". Admins who need more power can use httpd|nginx, ^web\d+, or (?i)example without needing a separate parameter.

The procs plugin has already been migrated to regex matching for --argument, --command, and --username (documented as a Breaking Change in the current CHANGELOG).

What needs to change

For each affected plugin:

1. Replace substring/startswith matching with re.search() (or re.match() where startswith semantics are needed).
2. Remove duplicate parameters where both --ignore-pattern and --ignore-regex exist for the same purpose. Keep the regex variant.
3. Update the help text to mention "Uses Python regular expressions." and case-sensitivity.
4. Document as a Breaking Change: simple filters like --ignore=httpd still work, but special regex characters (., *, (, [, \) in filter values are now interpreted as regex. Use --ignore='server\.local' to match a literal dot.

Backward compatibility

• Simple strings are valid regexes and match identically: httpd matches "httpd" in both modes.
• Startswith behavior can be expressed as ^httpd.
• Exact match can be expressed as ^httpd$.
• The only breakage is when existing filter values contain regex-special characters that were previously treated as literals (e.g. C:\Windows, server.local, file(1)).

Scope

All plugins that currently use substring, startswith, or in matching for filter parameters. The procs plugin is already done and serves as a reference implementation.

Classification

Breaking Change (next major version).