Resolve "implement pages"

This MR is supposed to introduce all features required as a MUST in the Web Annotation Protocol. Please review with utmost diligence.

You can get an overview of the expected features in OpenProject. Check or uncheck in the following list wether you think the feature request is met or not:

• 25117
  • The Annotation Server MUST support the following HTTP methods...
• 25118
  • Servers MUST support the JSON-LD representation...
• 25119
  • The response from the Annotation Server MUST have a Link header...
• 25120
  • For HEAD and GET requests, the response MUST have an ETag header...
• 25121
  • The response MUST have an Allow header...
• 25125
  • An Annotation Server MUST provide one or more Containers...
• 25126
  • The URI of an Annotation Container...
• 25128
  • The Annotation Server MUST support the following HTTP methods...
• 25129
  • When an HTTP GET request is issued against the Annotation Container...
• 25130
  • Annotation Containers MUST return a Link header...
• 25131
  • If the Accept header is absent from a GET request...
• 25133
  • The Collection MUST have an IRI that identifies it...
• 25134
  • If there are greater than zero Annotations in the Container...
• 25135
  • The IRI of the Container provided in the response... (see #9)
• 25137
  • The Annotation Page MUST have an IRI that identifies it...
• 25138
  • If the Page is not the last Page in the Collection...
• 25139
  • Each page MUST have a link to the Collection that it is part of...
• 25153
  • Upon receipt of an Annotation...
• 25154
  • The server MUST respond...

Closes #1 (closed)