Convert to TypeScript and adopt Promise

[heycalmdown]

TypeScript

• Converted to TypeScript
• Developers can use both ways - JS or TS
• Developers who is using JS also get benefits from typings

  Promise

• A modern way instead of callbacks
• Developers can use both ways - callbacks or promises

  Test

• Provides a test environment by Docker
• Developers don't need to set up their own a perforce server