[#220] Use JSON feed plugin for Akvo KPIs on seeithappen page

Edit the networkPage.php to use the JSON plugin to fetch and render the
KPI/dashboard data.

Add templates for the code snippets needed for the JSON feeds.
The snippets include info on the feed it is related to to facilitate
setup by someone other than me ;-)
[#220] Cleanup. Remove javascript and old html
Merge pull request #222 from akvo/feature/220_kpi_json_plugin

Reviewed: feature/220 kpi json plugin