Plugins should be published as separate packages

[Ben G]

Currently plugins are included directly in panop source, which locks users into specific output. We should switch to a model similar to Eslint where plugins are individually published to npm.

[Ben G]

In progress - have converted the repo to Lerna monorepo format.

Now need to split the packages/panop/src/plugins/* files into folders inside the packages dir.

[Ben G]

Done