chore: remove _isStarted as it's no longer used

_isStarted is an outdated property and shouldn't exist
in the code anymore. The state machine handles start
logic and the isStarted computed property pulls from there.
The code comments around dht and pubsub are also no
longer valid, so they were deleted.

src/index.js

@@ -53,7 +53,6 @@ class Node extends EventEmitter {
 
     this._modules = _options.modules
     this._config = _options.config
-    this._isStarted = false
     this._transport = [] // Transport instances/references
     this._discovery = [] // Discovery service instances/references
 
@@ -400,18 +399,13 @@ class Node extends EventEmitter {
         }
       },
       (cb) => {
-        // TODO: chicken-and-egg problem #1:
-        // have to set started here because DHT requires libp2p is already started
-        this._isStarted = true
         if (this._dht) {
           this._dht.start(cb)
         } else {
           cb()
         }
       },
       (cb) => {
-        // TODO: chicken-and-egg problem #2:
-        // have to set started here because FloodSub requires libp2p is already started
         if (this._floodSub) {
           return this._floodSub.start(cb)
         }