change module path from git.eeqj.de/sneak/neoirc to sneak.berlin/go/neoirc

Update go.mod module directive, all Go import paths, and JSON schema
$id URIs to use the new sneak.berlin/go/neoirc module path.

schema/commands/PUBKEY.json

@@ -1,6 +1,6 @@
 {
   "$schema": "https://json-schema.org/draft/2020-12/schema",
-  "$id": "https://git.eeqj.de/sneak/neoirc/schema/commands/PUBKEY.json",
+  "$id": "https://sneak.berlin/go/neoirc/schema/commands/PUBKEY.json",
   "title": "PUBKEY",
   "description": "Announce or relay a user's public signing key. C2S: client announces key to channel or server. S2C: server relays to channel members. Protocol extension (not in RFC 1459). Body is a structured object (not an array) containing the key material.",
   "$ref": "../message.json",