Feature: Set text to display in the background of a terminal instead of just an image

[jasonturner]

Description of the new feature/enhancement

Within Profile Settings add the ability to not only have a Background image but also background text. This is set-up within the Profile Settings as either within Background Image Settings or as its own group of properties.

Why: When using multiple profiles with lots of Tabs open its handy to be able to recognise which server etc I'm working on at any one time and having an opaque reminder is really handy. Currently I'm doing this with images (see Mockup Below), however it would be nicer to have the option to just add text to the background.

Example Mockup:

Proposed technical implementation details (optional)

Within Profile Settings and "list"

"list":
        [	   
            {
                // Make changes here to the powershell.exe profile.
                "guid": "{61c54bbd-c2c6-5271-96e7-009a87ff44bf}",
                "name": "Windows PowerShell",
                "commandline": "powershell.exe",
                "hidden": false,
		"backgroundText" : "IamServer1",
		"backgroundTextFontStyle" : "Bold",
		"backgroundTextFontSize" : "32",
		"backgroundTextFont": "Sans-Serif"
		"backgroundTextFontColor": "#93f533"
		"backgroundTextAlign": "centre"
		"backgroundTextOpacity": 0.1"
            },

[DHowett]

Thanks for the request, and I'm sorry to take so long to get back to you!
This isn't something we're likely to add to the core Terminal, but I think it would make a great extension idea.

Linking: #4000.