Fetch message for quotefast action via Msg object

[live627]

Motivation

I have a modification (Topic Descriptions) that needs access to this, so we'll use Msg::load() which eventually calls integrate_query_message

Idea

$query_customizations could become its own object.

[jdarwood007]

Haven't run the code but looks good.

I'm in support of more objects for everything. It makes things much easier to develop. But we have to contend with how it would support customizations. Magic methods maybe can help there.

[DiegoAndresCortes]

I like it, same thing we got for messageindex, the more places the better imo

[tyrsson]

From a customization perspective. If you model the instances that need to support customization as Observable then mods can be notified via their own registered listeners.