Include pipeline rule content/source matches when searching on `Pipeline Rules`

[coffee-squirrel]

What?

Searching on the Pipeline Rules page (i.e. /system/pipelines/rules) should include matches on pipeline rules' content/source.

Why?

This would make it easier to:

• identify use of certain functions (for reference when developing new rules, finding deprecated functions [e.g. remove_field in #19287], etc.)
• find other useful content (e.g. TODOs, system identifiers, IPs / CIDR ranges, etc.)

The current approach I use is to dump all pipeline rules via the API and search that content, but that's a bit tedious (and without parsing the JSON the content has \", \n, etc. all over the place).

Your Environment

• Graylog Version: 6.1.5

[patrickmann]

Here's another vote from the forums for better rule searching / management capabilities: https://community.graylog.org/t/finding-deprecated-funtions-in-pipeline-rules/35811/2?u=patrickmann