[CK_BUILDER] Debug utilities (#3528)

* ck-builder: make toString to_string

We are using snake case for CK-Builder

* ck-builder: add debug.hpp with tensor descriptor printing function

This adds some initial functionality to debug.hpp, a header which will
be used to house some debug utilities.

* ck-builder: abstract nd-iteration

Abstracting this makes it easier to test, clearer, and allows us to
use it elsewhere (such as in debug.hpp soon)

* ck-builder: tensor printing

* ck-builder: rename INT32 to I32

This makes it more in line with the other data type definitions.

experimental/builder/test/unit_validation.cpp

@@ -173,8 +173,8 @@ TEST(ValidationReportTests, MultipleSomeIncorrect)
     }
 
     {
-        auto desc = ckt::make_descriptor<ckb::DataType::INT32, 3>({'G', 'P', 'U'},
-                                                                  ckt::PackedRightLayout{});
+        auto desc =
+            ckt::make_descriptor<ckb::DataType::I32, 3>({'G', 'P', 'U'}, ckt::PackedRightLayout{});
 
         auto a = ckt::alloc_tensor_buffer(desc);
         auto b = ckt::alloc_tensor_buffer(desc);