The EventTarget implementation of libp2p contained workarounds for incomplete runtime support for the feature. One of the workarounds was specifically marked to be removed once CustomEvent was implemented in NodeJS and the [upstream ticket](nodejs/node#40678) was closed. This has happened two years ago. The implementation of the standard event in Node18 and the subsequent removal of the experimental flag in Node19 broke the current workaround and causes tsc to error. Some of these were suppressed with @ts-ignore, others were not. This fix closes #2420.

The fix removes the workaround as instructed by the source code and restores compatibility with recent versions of Node types.

Adds a connection monitor that periodically ensures remote peers are
still online and contactable by trying to send a single byte via the
ping protocol, and sets the `.rtt` property of the connection to how
long it took.

If the ping protocol is not supported by the remote, it tries to infer
the round trip time by how long it took to fail.

If the remote is unresponsive or opening the stream fails for any
other reason, the connection is aborted with the throw error.

It's possible to configure the ping interval, how long we wait before
considering a peer to be inactive and whether or not to close the
connection on failure.

Closes #2643

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Co-authored-by: Chad Nehemiah <chad.nehemiah94@gmail.com>

Creates two new metric counter groups for WebSockets: `libp2p_websockets_dialer_events_total` and `libp2p_websockets_listener_events_total`.

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Co-authored-by: achingbrain <alex@achingbrain.net>