* Start work on context aware backends
* Start work on moving the database plugins to gRPC in order to pass context
* Add context to builtin database plugins
* use byte slice instead of string
* Context all the things
* Move proto messages to the dbplugin package
* Add a grpc mechanism for running backend plugins
* Serve the GRPC plugin
* Add backwards compatibility to the database plugins
* Remove backend plugin changes
* Remove backend plugin changes
* Cleanup the transport implementations
* If grpc connection is in an unexpected state restart the plugin
* Fix tests
* Fix tests
* Remove context from the request object, replace it with context.TODO
* Add a test to verify netRPC plugins still work
* Remove unused mapstructure call
* Code review fixes
* Code review fixes
* Code review fixes
* database/mysql: Allow the creation statement to use commands that are not yet supported by the prepare statement protocol
* Remove unnecessary else block
* Fix the mysql legacy username length
* Remove boolean parameter
* Add a MySQL 5.6 container to test the legacy MySQL plugin against
* Add database plugins to the make file
* Fix credsutil test
