This commit implements the following behaviour:
1. adds a function clientPluginNames() to hooks.js (mimicking what is done in
static.js), which returns an array containing the list of currently installed
client side plugins. The array is eventually empty.
2. calls that function in pad.html at rendering time (thus server-side) to
populate a class attribute.
Example results:
- with no client-side plugins installed:
<div id="editorcontainerbox" class="">
- with some client-side plugins installed:
<div id="editorcontainerbox" class="ep_author_neat ep_adminpads">
Looking at the existing code (src/node/hooks/express/static.js#L39-L57), a
client-side plugin is defined as a plugin that implements at least a client side
hook.
NOTE: there is currently no support for notifying plugin removal/installation
to the connected clients: for now, in order to get an updated class list,
the clients will have to refresh the page.
Fixes#3488