[Releasing] Current beta installers

[Heikkinen Miikka]

> Can't we just start the vcredist installers with the /q switch to make
> them shut up like other installers do? I mean why let the user a choice
> to install them or not?
>    I find it quite annoying if some installer is running, I'm typing
> stuff in another window and suddenly there's a popup of yet another
> installer in the installer. :)

Looks like redistributables were originally using '/q' switch, but that was deliberately changed in subsequent commit - no explanation was given as to why: https://codereview.qt-project.org/#change,30254  

-Miikka