* use observer pattern for service discovery
* update perf standby method
* fix test
* revert usersTags to being called serviceTags
* use previous consul code
* vault isnt a performance standby before starting
* log err
* changes from feedback
* add Run method to interface
* changes from feedback
* fix core test
* update example
* move ServiceDiscovery into methods
* add ServiceDiscoveryFactory
* add serviceDiscovery field to vault.Core
* refactor ConsulServiceDiscovery into separate struct
* cleanup
* revert accidental change to go.mod
* cleanup
* get rid of un-needed struct tags in vault.CoreConfig
* add service_discovery parser
* add ServiceDiscovery to config
* cleanup
* cleanup
* add test for ConfigServiceDiscovery to Core
* unit testing for config service_discovery stanza
* cleanup
* get rid of un-needed redirect_addr stuff in service_discovery stanza
* improve test suite
* cleanup
* clean up test a bit
* create docs for service_discovery
* check if service_discovery is configured, but storage does not support HA
* tinker with test
* tinker with test
* tweak docs
* move ServiceDiscovery into its own package
* tweak a variable name
* fix comment
* rename service_discovery to service_registration
* tweak service_registration config
* Revert "tweak service_registration config"
This reverts commit 5509920a8ab4c5a216468f262fc07c98121dce35.
* simplify naming
* refactor into ./serviceregistration/consul
