Add Quick Notifications

Adds the Solid Quick Notifications Protocol that enables Solid Servers to directly provide clients with notification channels and/or let them negotiate subscriptions using HTTP headers within any GET requests.

README.md

@@ -12,6 +12,12 @@ These reports are incubated by the [Solid Notifications Panel](https://github.co
 * Editors Draft:
   * [Solid Notifications Protocol](https://solid.github.io/notifications/protocol)
 
+### Quick Protocol
+* Latest Published Version:
+  * [Solid Quick Notifications Protocol](https://solidproject.org/TR/quick-notifications-protocol)
+* Editors Draft:
+  * [Solid Quick Notifications Protocol](https://solid.github.io/notifications/quick-protocol)
+
 ### Notification Channel Types
 
 The Solid Notification Protocol makes it possible to define [notification channel types](https://solid.github.io/notifications/protocol#notification-channel-types). In order to help with the discovery of notification channel types that can be used with the Solid Notifications Protocol, it is encouraged to register them for maximum global interoperability at [Solid Technical Reports](https://solidproject.org/TR/#notification-channel-type-registry).

quick-notifications-flow-discovery.mmd

@@ -0,0 +1,7 @@
+sequenceDiagram
+  participant Subscription Client
+  participant Resource Server
+
+  Subscription Client ->> Resource Server: HEAD Resource (topic)
+  Resource Server ->> Subscription Client: Existing Notifications Channels
+  Resource Server ->> Subscription Client: Subscription Discovery

quick-notifications-flow-subscription.mmd

@@ -0,0 +1,7 @@
+sequenceDiagram
+  participant Subscription Client
+  participant Resource Server
+
+  Resource Server -->> Subscription Client: Discovery Response
+  Subscription Client ->> Resource Server: Subscription Request
+  Resource Server ->> Subscription Client: Subscription Response (with Notification Channel)