Re-Export Lib Functions in index.ts

[zsteinkamp]

Problem Statement

For users of njs-acme that want to develop their own flows, importing the utility functions requires less-than-ideal import syntax.

Proposed Solution

Re-export the library and client utility methods in index.ts.

From @ivanitskiy:

let's re-export all utils, and api/client so somebody can use them to implement their own request handler.