refactor: async routing (#489)

* feat: async routing

* chore: put dht extra api commands under content routing

* chore: add default option to createPeerInfo

Co-Authored-By: Jacob Heun <jacobheun@gmail.com>

* chore: address review

* chore: rm dlv

test/content-routing/dht/utils.js

@@ -0,0 +1,37 @@
+'use strict'
+
+const KadDht = require('libp2p-kad-dht')
+const { multicodec } = require('libp2p-kad-dht')
+const Crypto = require('../../../src/insecure/plaintext')
+const Muxer = require('libp2p-mplex')
+const Transport = require('libp2p-tcp')
+
+const mergeOptions = require('merge-options')
+
+const baseOptions = {
+  modules: {
+    transport: [Transport],
+    streamMuxer: [Muxer],
+    connEncryption: [Crypto]
+  }
+}
+
+module.exports.baseOptions = baseOptions
+
+const subsystemOptions = mergeOptions(baseOptions, {
+  modules: {
+    dht: KadDht
+  },
+  config: {
+    dht: {
+      kBucketSize: 20,
+      randomWalk: {
+        enabled: true
+      },
+      enabled: true
+    }
+  }
+})
+
+module.exports.subsystemOptions = subsystemOptions
+module.exports.subsystemMulticodecs = [multicodec]