Refactor

[JLuboff]

@bradtaniguchi Please review at your convenience. Refactored a good bit. Key points

• Changed ready method to dbReadyCheck
  • DB check to be async function instead of a function accepting a callback
• Created private method getExpirationDate as it was used within multiple methods
• Created private method queryRunner to handle DB check and running query
• Changed all public methods to async and updated syntax to go along with the new methods
• Use ternaries within return statements for more concise code
• Changed interface name from IMSSQLStore to MSSQLStoreDef
  • Kept IMSSQLStore by extending MSSQLStoreDef and commented it will be deprecated in v4.0
• Added missing test for clear method
  • Verified all tests passing

This will be v3.1.0 for publishing when ready.

[JLuboff]

@bradtaniguchi Run time of latest commits

• Resolved the above issues
• Removed unneeded returns
• Updated class interface methods to have return type of Promise<void> instead of void