Publishing stage filtering will now only apply to SkySat and PlanetScope data

[vermeulendivan]

Fixes #137

• When the Publishing stage filter where active, the search results will not include Landsat or Sentinel data
• Additional testing showed that the same happens with RapidEye
• The reasons for this is because neither of these satellite images has the "Publish stage" filtering option
• The "Publish stage" filtering will now only apply to SkySat and PlanetScope, as those are the only data which has this field in the metadata

PlanetScope footprint data (Publishing stage included):

Landsat footprint data (no publishing stage):

Results with PlanetScope, SkySat and Landsat:

Results with Landsat and Sentinel:

[vermeulendivan]

@Samweli Suggested change has been applied.