small renames/refactors in plugins

Signed-off-by: Tyler Schultz <tschultz@pivotal.io>
remove plugin rpc server and surrounding code

Signed-off-by: Tyler Schultz <tschultz@pivotal.io>
Remove unused plugin server port argument

Signed-off-by: Tyler Schultz <tschultz@pivotal.io>
plugins have names defined by method, instead of reflective struct name

Signed-off-by: Tyler Schultz <tschultz@pivotal.io>
simplify the plugin Run method

Signed-off-by: Tyler Schultz <tschultz@pivotal.io>
remove unneccessary localhost ip addresses

Signed-off-by: Tyler Schultz <tschultz@pivotal.io>
Exit 1 when a plugin exits nonzero or panics

[#81633932]

Signed-off-by: Tyler Schultz <tschultz@pivotal.io>