Remove deprecated rules

[ben-githubs]

Background

A number of rules in Panther are deprecated and not encouraged to be used. We have previously marked them as deprecated, but haven't had a good way to actually remove them from the repo without leaving orphaned versions on each customer's remote instance.

This PR creates a deprecated.txt file containing the RuleIDs of all rules we've removed. Customers can use this file to remove deprecated rules from their instances with:

make remove-deprecated

Additionally, we've added another make target, make check-deprecated, which is used in the new check-deprecated Action. This action checks the current branch/PR against release and determines if any rules have been removed recently and not added to deprecated.txt. The primary purpose of this Action is for our use as we clean up old rules moving forward to ensure we're tracking anything we delete.

Changes

• removed all rules marked as deprecated
• added a deprecated.txt file and appended the rule IDs of all the deleted rules
• added a script to check for deleted rules, and to delete anything listed in deprecated.txt
• added a GitHub Action to check for any deleted rules in a PR that aren't added to deprecated.txt

Testing

• make test, pat validate, and pat upload all worked successfully.
• made a test branch to confirm the check-deprecated workflow works as expected
• ran make remove-deprecated to delete rules from a test Panther backend

[jacknagz]

Love it. Do you know if we need also to do this with older IoCs?

[ben-githubs]

@jacknagz yeah, removing old IoCs was one of the motivators for this! We already have several IoC rules marked as deprecated that got cleaned out in this PR