Add toolbar buttons for top macros

In order to make the macro browser really visible and compelling, we need to consider ways of promoting it. The current approach (one tiny button opens up the whole browser, with an overwhelming amount of options) doesn't work for business-users, IMO.

We need a way to a) make the browser more visible, and b) to make the simple use-cases easier to use. Oh, and we have to do so with minimal amount of effort!

Therefore I propose we add 5 nicely designed buttons to the toolbar (into a separate toolbar section), which open 5 top macros on the second tab of the macro browser. These five macros should come with default values filled in in order to make the life of the user easier, and the preview tab should be pre-filled without having to click the preview button. Ideally those would be a combination of really useful macr

Table of Content
Content-by-User
Gallery macro
Recently updated
Blogposts macro

Assigning to Agnes to make the MB team aware of this. Not a scheduled task for 3.0 yet, but getting an estimate would be nice.