integrate isDeflate and isGzip

[Uzlopak]

integrate isDeflate and isGzip
remove corresponding packages from dependencies
wrote unit tests for the above functions

Checklist

• run npm run test and npm run benchmark
• tests and/or benchmarks are included
• documentation is changed or added
• commit message and code follows the Developer's Certification of Origin
  and the Code of conduct

[Uzlopak]

@kibertoad
@Fdawgs

I have to ask you to again review it. On a smoking break I realized that i can do the CMF header check in isDeflate with bit operations.

before:

valid x 223,947,412 ops/sec ±0.70% (90 runs sampled)
invalid x 831,593,213 ops/sec ±0.88% (93 runs sampled)

after:

valid x 1,027,199,609 ops/sec ±0.74% (89 runs sampled)
invalid x 1,038,269,211 ops/sec ±0.94% (91 runs sampled)

'use strict'

const { Suite } = require('benchmark')
const isDeflate = require('./lib/utils').isDeflate

const suite = new Suite()

const fakeDeflate = Buffer.from([0x78, 0x9d])
const fakeGzip = Buffer.from(Buffer.from([0x1f, 0x8b, 0x08]))

suite.add('valid', function () {
  isDeflate(fakeDeflate)
}).add('invalid', function () {
  isDeflate(fakeGzip)
})
suite
  .on('cycle', function (event) {
    console.log(String(event.target))
  })
  .on('complete', function () {
    console.log('Fastest is ' + this.filter('fastest').map('name'))
    console.log('Slowest is ' + this.filter('slowest').map('name'))
  })
  .run({ async: true })

[mcollina]

lgtm