[#859] Initial Google maps implementation for project, organisation and update listing

Reused the already existing global maps for projects and organisations, created a new map for updates. This is not an optimised version and should probably be revisited, but at least there is a map to show on every page.
Merge pull request #860 from akvo/feature/859_v3_maps

[#859] Initial Google maps implementation for project, organisation and update listings