Script Generator: show version number in About Dialog

[DominicOram]

As an instrument scientist I would like to be able to easily check the version of the standalone script generator e.g. in an about menu so that I know what version I am using for debugging purposes.

Acceptance Criteria

• The version of the standalone script generator is easily found from the GUI
• there is a squish test for this - spun out into Script Generator: Behaviour testing on standalone version #5218

[DominicOram]

Do at the same time as #6402

[davidkeymer]

Also consider completing #6229 to add IBEX logo to "About Box"

[JamesKingWork]

PRs:

• Script generator get version in UI ibex_gui#1297 Ticket6478 script gen version help ibex_gui#1298
• Can't have a squish test for this without doing Script Generator: Behaviour testing on standalone version #5218 first. I think it is out of the scope of this ticket but have added an acceptance criteria to the other ticket Toolbar is no longer being used for this functionality
• Squish: https://github.com/ISISComputingGroup/System_Tests_UI_E4/pull/92

Release notes: #6523