Provide better user feedback while 'Publishing to live'

[jaceq]

This is a followup of ticket: #87 (thanks @epugh for making a PR for #87 ) .
Now (that means in SMUI 3.13.1) process is that when someone clicks 'Publish to LIVE' a confirmation popup comes (as it should), when someone then clicks 'YES' then popup stays with buttons unlocked until a 'success confirmation' comes up.
Given that we use a custom script that takes a bit longer to 'Publish to LIVE' (as it includes a git push) having that popup on screen for a good few seconds is a bit confusing for our operators.
What would make sense would be to lock that popup somehow, eg (sorry for my bad graphical skills :) ):