Allow user to configure the default title displayed in browser

[jmiranda]

Make the ​title localizable by adding in a localizable message tag to all GSP layouts.

I think the easiest way to do this would be to add the following tag to all GSP layouts (custom.gsp, react.gsp, etc).

<title>${g.message(code: 'default.title.label', default: 'OpenBoxes')}</title>

A more customizable approach would be to use our hacky message taglib.

<title>${warehouse.message(code: 'default.title.label', default: 'OpenBoxes')}</title>

NOTE: The name "warehouse" was the original name of the application before we changed it to "openboxes". We'd like to either merge g.message and warehouse.message or change warehouse to openboxes. However, that will require a very large amount of changes so we're waiting until after we migration to Grails 3 (or now maybe Grails 5).