Allow KMZ filetype uploads for Layers

[ryanslatten]

This PR allows KMZ filetypes to be uploaded like a KML file. The KMZ file is unzipped before being uploaded.

To test: go to the Admin page and create a new Static Layer. Then attempt to upload a KML, KMZ, and any other file and verify that only KML and KMZ files succeed.

[paulsolt-ofsw]

A few issues:

1. The KMZ or KML files do not appear in the map preview on the Layers screen after it shows "Created 4 Features from File sample.KMZ"

2. Is there any way to edit multiple KML/KMZ files (remove layers?) - may be a separate backlog item

3. Minor: If I press upload before loading a file, it appears to load that file immediately, should the upload button be disabled until I have something to upload?

4. I cannot see the Camera.kmz file. This has styling, but even loading the file as .kml I don't see any points. Previously, @RyCarpenter had seen invalid image icons on the map.

5. Are we loading styling information from the .KMZ file? (Cameras.kmz) should have a custom icon.

6. Can you mention KML/KMZ in the places that showcase this feature.

[paulsolt-ofsw]

See my comment for details. We may need to write new stories to support this feature.

[paulsolt-ofsw]

Looks good! Thanks for the fixes.