Use uncertainties and mask from `Spectrum1D`

[nmearl]

This updates the Spectrum1D translator to also include the uncertainties and mask on the spectrum instance as glue components.

[codecov[bot]]

Codecov Report

Merging #19 into master will decrease coverage by 0.18%. The diff coverage is 91.37%.

@@            Coverage Diff             @@
##           master      #19      +/-   ##
==========================================
- Coverage   97.07%   96.89%   -0.19%     
==========================================
  Files          13       13              
  Lines         924      967      +43     
==========================================
+ Hits          897      937      +40     
- Misses         27       30       +3     

Impacted Files	Coverage Δ
...lue_astronomy/translators/tests/test_spectrum1d.py	97.34% <87.50%> (-2.66%)	:arrow_down:
glue_astronomy/translators/spectrum1d.py	97.22% <94.11%> (+1.14%)	:arrow_up:

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[eteq]

In some out-of-band conversation with @nmearl we discussed my test commit and agreed there's more to that than meets the eye, so to keep the "masks" discussion separate from the rest of this, I'll take out my test commit, merge this PR, and make a separate issue/PR about the mask question