TST: Add tests for unzipped data

[jklenzing]

Description

The unzip feature in download is required for pysatModels. However, there are currently no local instruments that require this.

Potential solution(s)

• add a local instrument that requires unzipping
• add fake data somewhere (needs to have https structure, github not sufficient)

Alternatives

Move the whole routine to the core package and sort it out there.

Additional context

TIMED SEE and SABER were the original candidates for this, but the netCDF files require major changes to the pysat load routines.