pelias-api used as lib

[stefanocudini]

Use-cases

useful for creating a wrapper for pelias api

Attempted Solutions

I want use this module as npm lib like this way:

const app = require('pelias-api/app');

contents of index.js

but now receive this error, I think that could be solved easily

node index.js 
2020-11-09T14:17:54.309Z - warn: [pip] pip service disabled
2020-11-09T14:17:54.310Z - warn: [placeholder] placeholder service disabled
2020-11-09T14:17:54.310Z - warn: [language] language service disabled
2020-11-09T14:17:54.311Z - warn: [interpolation] interpolation service disabled
2020-11-09T14:17:54.311Z - warn: [libpostal] libpostal service disabled
2020-11-09T14:17:54.311Z - warn: [libpostal] libpostal service disabled
fs.js:114
    throw err;
    ^

Error: ENOENT: no such file or directory, open './public/apiDoc.md'

[stefanocudini]

hi, I'm just created a simple generic solution in this PR #1640