insert plugin struct into state on init

[MrPicklePinosaur]

Previously if you wanted to add any form of configuration to a plugin, you would have to add a field to the plugin struct, then on initialization, create another struct with the field duplicated, copy the field over and insert the state. This was obviously really annoying, so now by default shrs will insert the plugin into state directly. This also provides a way to check if a plugin is installed to some extent