Sub tabs for General Messages Pane

What is the benefit? Why is this valuable?

Multiple different kind of topics are dumped under "General Messages" bottom pane which is making it hard to follow the relevant messages e.g. CMake output and QMake output when parsing projects, the output of user-defined external tools, and more. This is fixed by creating a "Tool Output" pane with tabs for individual "external" tools, and move the "Version Control" there and get rid of "General Messages"

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Requirements

• Merge  "General Messages" and "Version Control"  into one tab which has sub tabs for individual tools
• Remove "General message"

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