* Exclude None from `get_processor` return type annotation
An exception is raised in case of error, so it can't ever return None
* Add support for OGC API Processes Subscriber
The subscription URLs are passed to the manager, which
then has to call them appropriately.
By default, managers have the attribute `supports_subscribing`
set to `False` in order to not break the API for these. The
subscriptions are only passed to if this is set to `True`
* Add ogc api callback class to conformance
https://docs.ogc.org/is/18-062r2/18-062r2.html#toc67
* Make successUri mandatory in subscriber
It's mandatory in the standard.
Thx @ricardogsilva !
* Use snake case in python for fields which are camel case in the api
Thx @ricardogsilva !
* Add subscriber to method docstring
* Provide default value for subscriber for managers not supporting it
Thanks @ricardogsilva !
* Factor out notification call into methods
This increases reusability by other managers
Thanks @ricardogsilva !
* Add an example call for a process subscriber
* Change test urls to valid urls
* Third party imports in own block
Bernhard Mallinger
94ae782b6c