Ping a container/endpoint on document update

[csarven]

Feature proposed by Jens Wonke-Stehle:

"Ping a library/archive whenever a version of a research webdocument is saved" - https://twitter.com/wonkestehle/status/669187970168156160

"when you hit 'publish' it uses a to be specified way to notify a certain institution" - https://twitter.com/wonkestehle/status/669196303516180481

[csarven]

The 'Share' feature functionally meets this 'ping'. It is able to send an LDN notification to any target resource's inbox by inputting target's URI. The target in this case is a library/archive URI. The notification payload is an announcement that includes a timestamp, license, a note, and the initiating agent etc.

The notification payload in Share could be customised further: https://github.com/linkeddata/dokieli/issues/165