R4R: Gov tags cleanup

[rigelrozanski]

Separate tags into a package to avoid duplicate strings throughout - consistent with tags design in stake - also a teeny bit of non-breaking cleanup

I've labelled as breaking changes, because some of the tag names have changed (one typo, but mostly CamelCase to dash spaces)

• Updated all relevant documentation (docs/) - NEED TAGS documentation! (just opened Document Module Tags #1780)
• Updated all relevant code comments
• n/a Wrote tests
• Updated PENDING.md
• Updated cmd/gaia and examples/

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For Admin Use:

• Added appropriate labels to PR (ex. wip, ready-for-review, docs)
• Reviewers Assigned
• Squashed all commits, uses message "Merge pull request #XYZ: [title]" (coding standards)

[codecov]

Codecov Report

Merging #1781 into develop will increase coverage by 0.68%.
The diff coverage is 70.45%.

@@             Coverage Diff             @@
##           develop    #1781      +/-   ##
===========================================
+ Coverage    62.77%   63.46%   +0.68%     
===========================================
  Files          122      117       -5     
  Lines         7125     6914     -211     
===========================================
- Hits          4473     4388      -85     
+ Misses        2390     2270     -120     
+ Partials       262      256       -6

[cwgoes]

utACK, improved!