crypto/keys: move keybase and keyring to crypto/keyring/ dir

[fedekunze]

Description

re: #5819

Moves the keyring and keybase types to a keyring/ directory. Tendermint key types will follow in a later PR

---

For contributor use:

• 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.
• Code follows the module structure standards.
• Wrote unit and integration tests
• Updated relevant documentation (docs/) or specification (x/<module>/spec/)
• Added relevant godoc comments.
• Added a relevant changelog entry to the Unreleased section in CHANGELOG.md
• Re-reviewed Files changed in the Github PR explorer

---

For admin use:

• Added appropriate labels to PR (ex. WIP, R4R, docs, etc)
• Reviewers assigned
• Squashed all commits, uses message "Merge pull request #XYZ: [title]" (coding standards)

[alessio]

Brilliant! Even package names now make sense!

[codecov]

Codecov Report

Merging #5866 into master will decrease coverage by 0.04%.
The diff coverage is 66.66%.

@@            Coverage Diff             @@
##           master    #5866      +/-   ##
==========================================
- Coverage   32.32%   32.27%   -0.05%     
==========================================
  Files         353      355       +2     
  Lines       39476    39447      -29     
==========================================
- Hits        12760    12731      -29     
  Misses      25440    25440              
  Partials     1276     1276

Impacted Files	Coverage Δ
crypto/keyring/info.go	80.24% <ø> (ø)
crypto/keyring/base_keybase.go	74% <ø> (ø)
crypto/keyring/lazy_keybase.go	57.26% <ø> (ø)
crypto/keyring/output.go	58.13% <ø> (ø)
types/errors/errors.go	71.79% <ø> (ø)	⬆️
client/keys/types.go	100% <ø> (ø)	⬆️
crypto/keyring/codec.go	100% <ø> (ø)
client/context/context.go	32.86% <0%> (ø)	⬆️
x/auth/client/cli/tx_multisign.go	0% <0%> (ø)	⬆️
x/auth/types/txbuilder.go	23.4% <0%> (ø)	⬆️
... and 18 more

[alexanderbez]

LGTM (assuming no changes to business logic).

[alexanderbez]

Please fix GolangCI and then feel free to merge 👍