Introduce new Keybase implementation that can leverage
operating systems' built-in functionalities to securely store
secrets.
This chunk is extracted from @poldsam's original PR:
- #4754
Thanks: @alexanderbez
Add Keybase's ExportPrivKey()/ImportPrivKey() API calls to export/import
ASCII-armored private keys. Relevant keys subcommands are provided as well.
Closes: #2020
* add a bunch of tests, add DONTCOVER text tag
- Also fix flaky test (closes: #3559). Don't test values
returned by queries since there's no way to query a
specific height via REST.
* GetTempDir -> NewTestCaseDir