Implement general mechanism of script executing during genration

[mrtrizer]

Put all scripts to script folder in root of a module. All scripts of all modules are available for calling from the root project. In flappy_conf we have a special field with next structure defined:

"scripts": {
  "before_res_gen": ["generate_v8_wrappers()"],
  "after_res_gen":["generate_res_headers()"],
  "before_res_pack":[],
  "after_res_pack":[],
  "before_targert_gen":["clang_format()"],
  "after_targert_gen":[],
  "before_terget_build":[]
  "after_terget_build":["publish()", "codecov()"]
}

Also it could be possible to call scripts via flappy command like flappy gen cmake but custom one flappy clang-format