Provide functionality to find and locate template scripts

[imagejan]

It would be helpful to have a tool to quickly search for a specific script template in the Templates menu, as well as locating its source (i.e. from which jar file, from which update site).

Maybe some code of the ImageJ CommandFinder can be re-used for this, at it provides the same functionality for menu commands?

[imagejan]

With the new SearchActionFactory interface in place, it would probably sufficient to factor out the logic from here:

script-editor/src/main/java/org/scijava/ui/swing/script/TextEditor.java

Lines 870 to 926 in 5478a77

	/**
	* Initializes the Templates menu.
	* <p>
	* Other components can add templates simply by providing scripts in their
	* resources, identified by a path of the form
	* {@code /script_templates/<menu path>/<menu label>}.
	* </p>
	*
	* @param templatesMenu the top-level menu to populate
	*/
	private void addTemplates(final JMenu templatesMenu) {
	final File baseDir = appService.getApp().getBaseDirectory();
	for (final String templatePath : TEMPLATE_PATHS) {
	for (final Map.Entry<String, URL> entry : new TreeMap<>(
	FileUtils.findResources(null, templatePath, baseDir)).entrySet())
	{
	final String key = entry.getKey();
	final String ext = FileUtils.getExtension(key);
	// try to determine the scripting language
	final ScriptLanguage lang = ext.isEmpty() ? null :
	scriptService.getLanguageByExtension(ext);
	final String langName = lang == null ? null : lang.getLanguageName();
	final String langSuffix = lang == null ? null : " (" + langName + ")";
	final String path = adjustPath(key, langName);
	// create a human-readable label
	final int labelIndex = path.lastIndexOf('/') + 1;
	final String label = ext.isEmpty() ? path.substring(labelIndex) :
	path.substring(labelIndex, path.length() - ext.length() - 1);
	final ActionListener menuListener = new ActionListener() {
	@Override
	public void actionPerformed(final ActionEvent e) {
	loadTemplate(entry.getValue());
	}
	};
	// add script to the secondary language-sorted menu structure
	if (langName != null) {
	final String langPath = "[by language]/" + langName + "/" + path;
	final JMenu langMenu = getMenu(templatesMenu, langPath, true);
	final JMenuItem langItem = new JMenuItem(label);
	langMenu.add(langItem);
	langItem.addActionListener(menuListener);
	}
	// add script to the primary Templates menu structure
	final JMenu menu = getMenu(templatesMenu, path, true);
	final JMenuItem item = new JMenuItem(label + langSuffix);
	menu.add(item);
	item.addActionListener(menuListener);
	}
	}
	}

to generate a list of available templates that is usable by both the current script editor (when creating its Templates menu) and a newly created OpenTemplateActionFactory or some such.