This PR adds the option to set in-memory certificates to the API client instead of requiring the certificate to be stored on disk in a file.
This allows us to define API client TLS options per Consul secret backend in Vault.
Related issue hashicorp/vault#4800
* First conversion
* Use serf 0.8.2 tag and associated updated deps
* * Move freeport and testutil into internal/
* Make internal/ its own module
* Update imports
* Add replace statements so API and normal Consul code are
self-referencing for ease of development
* Adapt to newer goe/values
* Bump to new cleanhttp
* Fix ban nonprintable chars test
* Update lock bad args test
The error message when the duration cannot be parsed changed in Go 1.12
(ae0c435877d3aacb9af5e706c40f9dddde5d3e67). This updates that test.
* Update another test as well
* Bump travis
* Bump circleci
* Bump go-discover and godo to get rid of launchpad dep
* Bump dockerfile go version
* fix tar command
* Bump go-cleanhttp
