* Fix a couple of instances where we are using LIST verb
We specify it for the wrapping lookup function but for broader
compatibility with proxies and such we want to filter it to a GET. In a
couple of places we weren't doing that, so this updates those locations.
* Support registering plugin with name only
* Make RegisterPlugin backwards compatible
* Add CLI backwards compat command to plugin info and deregister
* Add server-side deprecation warnings if old read/dereg API endpoints are called
* Address feedback
* Add 'plugin list' command
* Add 'plugin register' command
* Add 'plugin deregister' command
* Use a shared plugin helper
* Add 'plugin read' command
* Rename to plugin info
* Add base plugin for help text
* Fix arg ordering
* Add docs
* Rearrange to alphabetize
* Fix arg ordering in example
* Don't use "sudo" in command description
Jeff Mitchell