Fixes for operating_system's display issues

[kruai]

This addresses two issues:

• ESSNTL-1725: When the operating_system's minor version is set to 0, it won't display "RHEL 8.0", for instance; it will just say "RHEL". That's because the component does not differentiate between falsy values.
• ESSNTL-1717: The "Release" field on the host detail page uses the deprecated system_profile.os_version field, instead of system_profile.operating_system.

I was going to make separate PRs for these, but they ended up being too tightly coupled. I refactored a bit so that we could reuse OperatingSystemFormatter; this added a <span> around the Release value, so I had to update the snapshots as well. There isn't isn't a visible change in the formatting, though the Release field now includes the name, e.g. "RHEL 8.0" instead of "8.0". Is that an issue?

[codecov-commenter]

Codecov Report

Merging #1451 (d6df2e2) into master (249bdfc) will not change coverage.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##           master    #1451   +/-   ##
=======================================
  Coverage   76.07%   76.07%           
=======================================
  Files          85       85           
  Lines        1806     1806           
  Branches      699      699           
=======================================
  Hits         1374     1374           
  Misses        379      379           
  Partials       53       53           

Impacted Files	Coverage Δ
src/components/GeneralInfo/selectors/selectors.js	75.75% <ø> (ø)
src/Utilities/OperatingSystemFormatter.js	100.00% <100.00%> (ø)
...ralInfo/OperatingSystemCard/OperatingSystemCard.js	90.00% <100.00%> (ø)
src/store/entities.js	31.42% <100.00%> (ø)

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