* backend_plugins: (34 commits)
  code style fixes
  Adds Table in backend datasource contract.
  Adds Tables types to protobuf
  Review tsdb protobuf contract
  supports windows compatible plugin binaries
  moves plugin proxy to plugin package
  improves name for plugin logger
  uses pluginmanagers log instead of global
  removes commented code
  makes datasource handshake more explicit
  backend plugins: improves logging
  dont spawn new subprocess while shutting down
  plugins: restart killed plugins
  query result should be a map
  test for plugin path builder
  merge backend datasources and datasources
  use int64 for timestamps
  fixes invalid valud/timestamp order
  merge backend-datasource and datasource type
  fixes broken unit test
  ...