filter: Middleware should keep blocked cached response

[qdm12]

for the ttl of the dns response, the cache should keep the response if it's blocked, to avoid re-fetching something blocked.

• remove https://github.com/qdm12/dns/blob/68ee053d8bc424cd58f0739f0a155ed68708fcf1/pkg/filter/middleware/middleware.go#L48
• remove cache injection to filter Middleware
• remove Remove method on cache

[qdm12]

Done in 4e69763118ba080548293eef14b8670414f686c0