* feat: Detects shard changed when using websockets.

* squash: Simplifies code.

* squash: Rename method.

* squash: Skips checking for shard changed on the initial connection.

* fix: Always query the main domain for features.

* squash: Always use the main domain for turn credentials and ping.

* squash: Fix tests.

* feat: Skips pinging when there was a recent server response.

* feat: Adds options to control xmpp ping settings.

* fix: Fixes wrong default value.

* squash: Received messages in ping interval sets failed ping to 0

The XmppConnection will try to resume the connection
only when the internet is online. This speeds up the process
by avoiding unnecessary connect attempts while offline as each
failed attempt increases the backoff delay.

If ping timeouts two times in a row (25 seconds total)
the XMPP WebSocket connection will be killed and restarted.

..readyState to tell if the connection is connected.

An 'item-not-found' or other error on Websocket reconnect will refresh
the timestamp which will give misleading information about when
the last stanza was received.

A new method which not only has Promise interface,
but also allows to queue IQs regardless of the current
connection's status.

Ping and send ICE failed notification requests are changed
to use this method which makes it more reliable on XMPP
Websocket connections on mobile(which in contrary to BOSH
dies much faster there).

The 'searchParams' are not implemented on react-native.

Copy/paste mistake - there's no such thing as this.connection in
the XmppConnection. Hard to track down because no error is logged.

Either connect or attach can be used to initiate the connection.

Use the rest argument expression to not miss any.

When Jiconop is used to attach to a warmed up BOSH session Strophe goes
to ATTACHED instead of the CONNECTED state.

The LastSuccessTracker has direct access to the Strophe.Connection.

The XMPP stream resumption will enable automatically if supported by
Prosody on Websocket connections. Pass the 'enableWebsocketResume'
config option set to 'false' to disable.

Websocket keep alive is HTTP GET request sent on the service URL passed
to Strophe. It is used to keep the stick tables alive. The feature comes
in enabled by default whenever Websocket are used. Pass
'websocketKeepAlive' config option set to -1 to disable.

See the code for more details about the default interval value.

The connected flag is flipped to true as soon as transport connection is
established by Strophe(such as WebSocket TCP), but it doesn't mean that
the connection is ready to send stanzas yet.

All calls to connection.send should go through the wrapper in order to
prevent breaking the connection by calling it in the not connected
state.

This prevents from accessing Strophe internals directly and allows to
block 'send' calls while disconnected. The latter breaks the stream
resume logic by putting stanzas onto the send queue.

TODO make jitsi strophe plugins use the XmppConnection wrapper whenever
possible instead of interacting with the Strophe.Connection directly.