Add IntelliJ IDEA theme plugin

[Roboron3042]

Nice to see someone working on a proper IDE theme!

I have some suggestions:

• Use #f57800 (Orange) for strings. Leave red for errors.
• Use #321959 (Transparent Purple) instead of #711c91 (Purple) for background where text is involved (i.e.: selections) for increased contrast.
• Use #133e7c (Light-Blue) for comments (although I am not so sure about this one).
• There are quite a lot of gray left (line numbers, buttons, separators...). Is that not themeable?

It is not perfect, but you have some guidelines at https://github.com/Roboron3042/Cyberpunk-Neon/wiki/Extended-Colorscheme. You may also want to take a look at the VIM theme for inspiration. It's the closest to a IDE theme I've done... Although I have been thinking about doing one for VSCode for quite a while, and I may do so next.

Anyway, thank you for your contribution!

[SIDSSIDS]

I'm a backend developer and I understand nothing in getting things look pretty )) this is my first experience

I will try to follow your color suggestions. And yeh, I know about gray things, it's quite hard to understand how to apply the desired colors to them. The documentation is poor.