Add ability to use custom templates for message/template items

[MartinLyne]

So I just got into using notifications and feel that the messages have an overly strict template. Fixed date format, requires a from-user and click url.

Wanted to gather some thoughts, expanding the Interface/s to require a getTemplateName ("YourBundle::template.html.twig") that replaces the normal template if found.

I'm still mulling that in my head. the alternative is.. I make a whole new event, a more generic notification that allows you to customise the navbar icon (currently stuck with bell for general, envelope for message) and uses the same custom template solution as above for rendering each item.

Currently got a bad cold, so if any of this has an easier solution or just sounds like fever dreams, please, let me know.

[avanzu]

A general solution would be to use a single kind of navbar event which provides some kind of attributed storage (like the session flashbag does).
Like so:

$event->getBag()->add('notification', new Notification()); 

Navbar segments would then be rendered using the attribute name to determine the actual twig template like so:

{% for type, items in bag %}
{% include 'YourBundle::' ~ type ~ 'html.twig' with { "items" : items } %}
{%endfor %}

In order to simplify the actual template markup, using a macro or generalized embed might be useful.