Add static scale_factor/add_offset/_FillValue to awips_tiled GLM config

[djhoese]

This is purely a configuration change to the configuration file used by the awips_tiled writer. This change is specific to the GLM "Full Disk" file scheme used by AWIPS and only effects the "Flash_extent_density" variable. The reason for this change is an apparent bug in AWIPS where for only the FED variable, the scale_factor/add_offset/_FillValue are ignored. In the best case we would use a scale_factor of 1.0 and add_offset of 0.0, but AWIPS, for some reason, does not allow "identity" scalings so 1.0 is not allowed. The change in this PR makes the scale_factor as close to 1.0 as possible for a 32-bit float so that the values in the file should nearly represent the original values.

The AWIPS bug is still being investigated, but in the mean time this workaround should be backwards compatible and allow us to continue our work.

[codecov]

Codecov Report

Merging #1537 (01e0908) into master (e0f1fb8) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master    #1537   +/-   ##
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  Coverage   91.65%   91.65%           
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  Files         248      248           
  Lines       36172    36172           
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  Hits        33155    33155           
  Misses       3017     3017           

Flag	Coverage Δ
behaviourtests	4.35% <ø> (ø)
unittests	92.19% <ø> (ø)

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[mraspaud]

LGTM