[IDEA] Graduate from C codes generation with ERB

[sonots]

Background:

• Cumo started as a fork of Numo. Numo has used ERB to generate C codes from 10 years ago (Maybe, C++ was not so good at that time).

Problem:

• We currently can not use C source codes formatter such as clang-format because it breaks erb formatting.

Replacement candidates:

• C++ template