feat: add certifi/idna/packaging/six type decl

crates/erg_compiler/lib/external/idna.d/__init__.d.er

@@ -0,0 +1,18 @@
+.core = pyimport "./core"
+
+{
+    .alabel;
+    .check_bidi;
+    .check_hyphen_ok;
+    .check_initial_combiner;
+    .check_label;
+    .check_nfc;
+    .decode;
+    .encode;
+    .ulabel;
+    .uts46_remap;
+    .valid_contextj;
+    .valid_contexto;
+    .valid_label_length;
+    .valid_string_length;
+} = .core

crates/erg_compiler/lib/external/idna.d/core.d.er

@@ -0,0 +1,33 @@
+.IDNAError: ClassType
+.IDNABidiError: ClassType
+.IDNABidiError <: .IDNAError
+.InvalidCodepoint: ClassType
+.InvalidCodepoint <: .IDNAError
+.InvalidCodepointContext: ClassType
+.InvalidCodepointContext <: .IDNAError
+
+.valid_label_length: (label: Str or Bytes) -> Bool
+.valid_string_length: (label: Str or Bytes, trailing_dot: Bool) -> Bool
+.check_bidi: (label: Str, check_ltr := Bool) -> Bool
+.check_initial_combiner: (label: Str) -> Bool
+.check_hyphen_ok: (label: Str) -> Bool
+.check_nfc: (label: Str) -> Bool
+.valid_contextj: (label: Str, pos: Int) -> Bool
+.valid_contexto: (label: Str, pos: Int, exception := Bool) -> Bool
+.check_label: (label: Str or Bytes) -> NoneType
+.alabel: (label: Str) -> Bytes
+.ulabel: (label: Str or Bytes) -> Str
+.uts46_remap: (domain: Str or Bytes, std3_rules := Bool, transitional := Bool) -> Str
+.encode: (
+    s: Str or Bytes,
+    strict:= Bool,
+    uts46:= Bool,
+    std3_rules:= Bool,
+    transitional:= Bool,
+) -> Bytes
+.decode: (
+    s: Str or Bytes,
+    strict:= Bool,
+    uts46:= Bool,
+    std3_rules:= Bool,
+) -> Str