* upgraded the protocol id to version 2 (i.e. /kad/2.0.0) and made it so v2 peers running in server mode respond to queries from v1 peers. Note: v2 peers will only send queries using the v2 protocol, will only add v2 peers to their routing tables, and will only tell v1 peers about v2 peers.
* to run a forked network we now use network specific protocol prefixes instead of manually setting protocol IDs. Use the ProtocolPrefix option instead of the Protocols option.
* emit errors during initialization if the user misuses the default protocol prefix by setting parameters inconsistent with the default protocol's network specification
* since the Client option has been deprecated it's been removed from the dht's options. While deprecated it is still available in the dht options package. Setting `Client(false)` now puts the node into ModeAuto.
* feat: move options to main package and make internals private
Rationale:
1. This allows us to make private options for testing.
2. This removes an import for DHT users.
3. This makes options much easier to discover.
4. This makes it possible to make the config/options internals private.
We originally put them in a sub-package to avoid poluting the root namespace,
but that isn't really necessary.
This keeps the old package (for now) to avoid breaking too much.
