Restructure developer "Welcome" page

[JayFoxRox]

I suggest the following changes to the websites developer Welcome page:

"Community":

• Section should be renamed to "Developer IRC / Discord" so visitors spot buzz-words.
• "XQEMU User Chat" should not be mentioned on Developer page, instead, an "Attention" box should just redirect users to the user portion (which then links to their Discord).

"Repository info":

• Probably most important, and should be the first section on top, followed by Build-Status.
• Also should have a GitHub logo as hint.

"Building From Source Code":

• Should not be a headline (will be in sidebar anyway)
• Can just be a link that's mentioned in the "Repository info" section.

"Debugging Guest Code":

• Should be its own article.

"Debugging XQEMU Itself":

• Should be its own article
• More important than guest debugging, so should be mentioned before guest debug.