Automated harvesting with sharepoint and etools

[timlinux]

So here is what we need @meomancer

1. New Sharepoint Harvester for indicators. Workflow will be much like the spreadsheet uploader except you pass a URL instead of a file. The mappings of sheet, geog, value, extra values should be saved as part of the harvester configs. Keep the manual uploader as we currently have it too please.

2. Meta harvester. Add a cog button next to the current button and have a harvester config much like the current one but also using sharepoint URI and doing concept mappings as above.

3. Add a new etools harvester - I guess that will need some api end point configs similar to existing API. Maybe we can use our current API harvester withouth making something new.