#80 GUI prototype

[slskiba]

Closes #80
Shows a welcome message in the window.
Display the cli project's version in the window title as poc of module dependency.

[CLAassistant]

All committers have signed the CLA.

[hohwille]

@slskiba thanks for this PR. You really have quickly jump started into the project and already implemented a working solution for the story 👍
As always I am picky and give you lots of review comments for improvement.
Also I am aware that you marked this PR as draft so it is WIP and maybe some of my points are already on your todo list...
I hope my comments help you to continue and improve.

[coveralls]

Pull Request Test Coverage Report for Build 9496934290

Details

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.002%) to 59.806%

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Totals
Change from base Build 9481759920:	0.002%
Covered Lines:	4679
Relevant Lines:	7536

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💛 - Coveralls

[hohwille]

@slskiba thanks for your rework. Looks nice now.
I added the java.version to the top-level POM. Could you remove it from the cli/pom.xml since it is redundant otherwise (could not do that easily in the browser).

[hohwille]

@slskiba thanks for perfectly addressing all my review comments.
Now ready for merge.