[doc] Improve code with readme.md in folders

[vinicius73]

add an readme.md in some folders

Client

• /client/src
• /client/src/app
• /client/src/app/auth/components
• /client/src/app/auth/routes
• /client/src/app/auth/vuex
• /client/src/components
• /client/src/root
• /client/src/router
• /client/src/store