fix struct/interface/logic conversion interactions

- interface conversion only waits for type resolution of modports
- typeof conversion resolves struct field accesses
- logic conversion only converts logic data declarations
- struct conversion only converts within modules
- fix nested type traversal order causing premature struct conversion

test/basic/interface_struct.v

@@ -0,0 +1,12 @@
+module top;
+    wire [3:0] i_x;
+    reg [1:0] i_w;
+    assign i_x = 4'b1001;
+    initial i_w = 2'b10;
+    initial begin
+        $display("%b", i_x[3]);
+        $display("%b", i_x[2]);
+        $display("%b", i_x[1]);
+        $display("%b", i_x[0]);
+    end
+endmodule