GNIP-53: APIs to decouple import and load of GeoNode Client Libraries

[afabiani]

Currently the load of a GIS client library on GeoNode, is done through a set of if - else statements on the templates, like, as an instance:

  {% if preview == 'geoext' %}
    {% include "layers/layer_geoext_map.html" %}
  {% elif preview == 'OL3' %}
    {% include "layers/layer_ol3_map.html" %}
  {% elif preview == 'react' %}
	{% include 'geonode-client/layer_map.html' %}
  {% else %}
    {% include "layers/layer_leaflet_map.html" %}
  {% endif %}

The proposal here would be to somehow include the client libraries from settings by dynamically loading the inclusion template headers through a custom tag library.

What I would like to achieve is something like changing the client library by simply adding the dependency to GeoNode and doing something like this on local settings

GEONODE_CLIENT_HOOKSET = "mygeonode.client.hooksets.MyNewReactHookSet"

and have the pages automatically switch the GIS client.