feat(streaming): implement stream key management

[onyedikachi-david]

/claim #41 Fixes: #41

• Add RTMP URL and Stream key fields to the streaming form
• Implement reset and copy functionality for stream key
• Add backward compatibility for users without stream keys
• Display toast notification when copying stream key

[onyedikachi-david]

[zcesur]

Getting this error:

[error] GenServer #PID<0.882.0> terminating
** (KeyError) key :stream_key not found in: %Membrane.RTMP.Messages.Connect{
  app: "live",
  tc_url: "rtmp://localhost:9006/live",
  flash_version: "FMLE/3.0 (compatible; FMSc/1.0)",
  swf_url: "rtmp://localhost:9006/live",
  fpad: nil,
  audio_codecs: nil,
  video_codecs: nil,
  video_function: nil,
  page_url: nil,
  object_encoding: nil,
  extra: %{"type" => "nonprivate"},
  tx_id: 1.0
}

Pretty sure it should be exposed in a param inside one of the validate_xyz handlers

[CLAassistant]

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