update sequence diagrams

[elf-pavlik]

TODO

• [ ] update each subscription type diagram
• [x] adjust notification channel terminology based on #131
• [x] remove authentication markings

Previews

sequenceDiagram
  participant Subscription Client
  participant Resource Server
  participant Subscription Server

  Subscription Client ->> Resource Server: HEAD Resource (topic)
  Resource Server ->> Subscription Client: HTTP Link rel="describedby"
  Subscription Client ->> Resource Server: GET Description Resource
  Resource Server ->> Subscription Client: Description Resource
  Subscription Client ->> Subscription Server: Subscription Request
  Subscription Server ->> Subscription Client: Subscription Response (with Notification Channel)

sequenceDiagram
  participant Notification Receiver
  participant Notification Sender

  loop while subscription active
    Notification Receiver ->> Notification Sender: Establish connection to the receiveFrom
    Notification Sender -->> Notification Receiver: Stream notifications
  end

sequenceDiagram
  participant Notification Sender
  participant Notification Receiver

  loop while subscription active
    Notification Sender ->> Notification Receiver: Send notifications to the sendTo
  end