snkrj: move database struct to its own crate

Cargo.lock

@@ -1524,9 +1524,9 @@ dependencies = [
  "regex",
  "reqwest",
  "rlimit",
- "sanakirja",
  "serde",
  "serde_json",
+ "snkrj",
  "struct_iterable",
  "swc",
  "swc_common",
@@ -2621,6 +2621,13 @@ dependencies = [
  "version_check",
 ]
 
+[[package]]
+name = "snkrj"
+version = "0.1.0"
+dependencies = [
+ "sanakirja",
+]
+
 [[package]]
 name = "socket2"
 version = "0.5.7"