Dynamic loading/unloading of plugins (#4259)

* First pass at dynamic loading/unloading

* Show warning for changes to plugins containing JS modules

* Use $:/config/RegisterPluginType/* for configuring whether a plugin type is automatically registered

Where "registered" means "the constituent shadows are loaded".

* Fix the info plugin

The previous mechanism re-read all plugin info during startup

* Don't prettify JSON in the plugin library

* Indicate in plugin library whether a plugin requires reloading

* Display the highlighted plugin name in the plugin chooser

And if there's no name field fall back to the part of the title after the final slash.

core/ui/ControlPanel/Modals/AddPlugins.tid

@@ -7,6 +7,7 @@ subtitle: {{$:/core/images/download-button}} {{$:/language/ControlPanel/Plugins/
 <$list filter="[<assetInfo>get[original-title]get[version]]" variable="installedVersion" emptyMessage="""{{$:/language/ControlPanel/Plugins/Install/Caption}}""">
 {{$:/language/ControlPanel/Plugins/Reinstall/Caption}}
 </$list>
+<$reveal stateTitle=<<assetInfo>> stateField="contains-javascript" type="match" text="yes">{{$:/language/ControlPanel/Plugins/PluginWillRequireReload}}</$reveal>
 </$button>
 \end
 
@@ -35,7 +36,7 @@ $:/state/add-plugin-info/$(connectionTiddler)$/$(assetInfo)$
 </$list>
 </div>
 <div class="tc-plugin-info-chunk">
-<h1><$view tiddler=<<assetInfo>> field="description"/></h1>
+<h1><strong><$text text={{{ [<assetInfo>get[name]] ~[<assetInfo>get[original-title]split[/]last[1]] }}}/></strong>: <$view tiddler=<<assetInfo>> field="description"/></h1>
 <h2><$view tiddler=<<assetInfo>> field="original-title"/></h2>
 <div><em><$view tiddler=<<assetInfo>> field="version"/></em></div>
 </div>