R4R: Support min fees in a localnet and fix gaiad config

[alexanderbez]

• Support minimum fees on a local testnet (default 1stake)
• Fix parsing/loading gaiad config (it was never being parsed/respected when it already existed)

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• Targeted PR against correct branch (see CONTRIBUTING.md)

• Linked to github-issue with discussion and accepted design OR link to spec that describes this work.

• Wrote tests

• Updated relevant documentation (docs/)

• Added entries in PENDING.md with issue #

• rereviewed Files changed in the github PR explorer

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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 #3172 into develop will decrease coverage by 0.01%.
The diff coverage is 4.54%.

@@             Coverage Diff             @@
##           develop    #3172      +/-   ##
===========================================
- Coverage    54.88%   54.86%   -0.02%     
===========================================
  Files          132      132              
  Lines         9446     9452       +6     
===========================================
+ Hits          5184     5186       +2     
- Misses        3943     3947       +4     
  Partials       319      319

[jackzampolin]

Nice! Tested locally too!

[alessio]

ACK. Just a little remark: this should be listed as breaking change due to a exported function in baseapp (SetMinimumFees) being unexported.