magic_firewall_ruleset: deprecate in favour of generic ruleset methods
magic_firewall_ruleset: deprecate in favour of generic ruleset methods

Magic Firewall Rulesets were the original edge rules engine
implementations however, now, we have a more robust and deeper
integration with the generic ruleset methods where `magic_transit` lives
along side the ever growing configuration options available in ERE.

cloudflare/cloudflare-go,cloudflare/cloudflare-go