Apply prettier to all directories

[Metastasis]

I would like to propose adding other folders (such as samples and test folders) to format script

Something like this

{
  "format:code": "prettier --write \"**/*.{js,ts}\""
}

[Siemienik]

It is great idea, however we have to be sure do not format node_modules and dist.

I've also created issue #64, where i suggest replace prettier by eslint.

Further I am thinking about doing format automatically by GittHuba test (similar like for markdown)