restructure the directory layout

[joyeecheung]

• steps -> components because I think that's a better name.
• Put queries under lib
• ./bin/get_metadata.js -> ./bin/get-metadata

New structure:

.
├── CONTRIBUTING.md
├── LICENSE
├── README.md
├── appveyor.yml
├── bin
│   └── get-metadata
├── components
│   └── metadata.js
├── lib
│   ├── queries
│   │   ├── PR.gql
│   │   └── ...
│   ├── args.js
│   └── ...
├── package-lock.json
├── package.json
└── test
    ├── fixtures
    │   └── ...
    └── unit
        └── ...

[codecov]

Codecov Report

Merging #113 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master     #113   +/-   ##
=======================================
  Coverage   91.01%   91.01%           
=======================================
  Files          14       14           
  Lines         534      534           
=======================================
  Hits          486      486           
  Misses         48       48

Impacted Files	Coverage Δ
lib/pr_data.js	100% <ø> (ø)	⬆️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 5c42f35...07c527c. Read the comment docs.

[joyeecheung]

This is spinning-off from my local branch of #106 , I am going to put the git sub commands into components. Also if we were going to put other tools managed by the automation team into this repo, I would also put the subtrees into components as well.

[joyeecheung]

CI looks happy, trivial change, so I'll merge this now.