Integrate ExCheck

[byhbt]

Why

ex_check (https://hexdocs.pm/ex_check) is an all-in-one command, which helps developers run the common checks for Elixir Application within 1 command. Supporting checks are listed in this document https://hexdocs.pm/ex_check/Mix.Tasks.Check.html#module-tools.

It's quite handy when the developers only need to remember one check command to execute: mix check, instead of remembering multiple separate commands and execute it manually.

Who Benefits?

Elixir Developers

[andyduong1920]

I voted No as

1. We had the mix codebase and mix codebase.fix which contained all checks for our code
2. We don't need to add 1 more 3rd library into the app

[andyduong1920]

@byhbt any update on this RFC