changes to temperature colors (2m T, sfc T, soil T, and T_2ds)

[cshartsough]

These color table changes were requested to improve the various temperature graphics:

• sfc T
• 2m T
• T 2ds
• soil T Sample graphics provided below.

passed pylint but failed pytest, will provide fix for that as needed.

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[cshartsough]

Note: The PR passed the pytest stage(s) on GitHub after failing on my own tests, so it appears to be an issue of me updating my pytests. I'll try to do that in the near future.