More configuration options

• remove NetworkExtensions dependency (not needed anymore) (#4)
• make monitoring a netservice optional (helpful, when you just want to resolve a service)
• make resolving of addresses and publishing of TXT also optional

First release

First release, offering Publishers for each of Apple delegates (NetServiceBrowser, NetService, NWBrowser and NWEndpoint).

Use of NWBrowser is recommended, as it's the newest API, from that you will use NWEndpoint to interrogate the endpoint about its metadata and IP. Internally, NWEndpoint will use NetService delegate for some informations.

The old path, also possible with this library, is using NetServiceBrowser to fetch services (NetService) and from that request TXT records and IP address of each service. Although this works well, it's not possible to capture certain unhappy paths, such as Network Permission revoked error.