message: Update CODING_STYLE.md
  Update CODING_STYLE.md to add 'east const' coding style rule.
diff: - function parameters: lowerCamelCase with leading underscore
  - Template parameter name: UpperCamelCase
  - preprocessor definitions: `SCREAMING_CASE`
  +- east const instead of west const
  ### Example
  ```cpp
  namespace org::coding_style::naming_conventions
  {
  + void eastConst() {
  + int const a = 42; // a is const
  + int const* p = &a; // value in p is const, p is not const.
  + int const *const p = &a; // both value and p are const.
  + }
  +
  enum class Role { Employed, Unemployed };
  struct User
  