Drop on-disk keybase in favor of keyring

[alessio]

This changeset aims to adapt gaia to the changes introduced in
cosmos/cosmos-sdk#5180

Rationale for this work is articulated in

• https://github.com/cosmos/cosmos-sdk/blob/master/docs/architecture/adr-006-secret-store-replacement.md

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• Linked to github-issue with discussion and accepted design OR link to spec that describes this work.
• Wrote tests
• Updated relevant documentation (docs/)
• Added a relevant changelog entry to the Unreleased section in CHANGELOG.md
• Reviewed Files changed in the github PR explorer

---

For Admin Use:

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

[codecov-io]

Codecov Report

Merging #164 into master will increase coverage by 0.74%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master     #164      +/-   ##
==========================================
+ Coverage   65.72%   66.46%   +0.74%     
==========================================
  Files           5        5              
  Lines         493      492       -1     
==========================================
+ Hits          324      327       +3     
+ Misses        138      134       -4     
  Partials       31       31

[alessio]

This is ready for preliminary review, although it should not be merged til cosmos/cosmos-sdk#5180 is merged first

[fedekunze]

@alessio is this R4R?

[alessio]

Yes @fedekunze, it is de facto R4R. I didn't tag it yet as such 'cause I was waiting for the SDK's respective PR to be merged first.

EDIT: I actually tagged it, @alexanderbez rightly removed the tag because it was blocked on the SDK's PR. But please feel free to review it, it's in fact ready and should be used to test the new keyring integration.

[fedekunze]

Changes LGTM, I have some questions only. Once those are replied/addressed I'll merge the implementation on the SDK

[alessio]

FYI I've carried out some code clean up.

[fedekunze]

tested ACK. @alessio mind updating this branch to latest SDK master?

[alessio]

Will update tests ASAP

[alessio]

All sorted @fedekunze

[fedekunze]

ACK. Thanks @alessio. We’ll probably have to write down the key migration guides for the next major release (cosmoshub-4) wiki and more docs for each OS.