Add OISD NSFW blocklist to the list

### Prerequisites - [x] The blocklist is created specifically for DNS-level blockers; - [x] The blocklist is regularly updated (at least 10 updates per month); - [x] The blocklist is known and popular; - [x] The blocklist satisfies [the repo requirements](https://github.com/AdguardTeam/HostlistsRegistry#-what-blocklists-can-be-added-here); ### Blocklist name oisd nsfw ### Blocklist category Other ### Homepage https://nsfw.oisd.nl ### Explanation Right now, adguard-dns.io only offers a simple toggle for nsfw websites. I prefer the oisd list for blocking nsfw.