Accounts API, VS Code Support and Quality improvements

Added

• Accounts API #13 #2
• Support for Linting #14
• Support for VS Code #20
• OSS files
  • CONTRIBUTING.md #19
  • CODE_OF_CONDUCT.md #17
• GitHub configurations
  • Security policy #20
  • Issue templates #18
  • Pull Request templates #18

Fixed

• Linting issues #14
• Fixed typo in README #15

Improved

• Type definitions #14