Rework UI

[Deewarz]

• Required by: https://github.com/MafiaHub/MafiaMP/pull/102

Global

• Add a way to disable processing of mouse and keyboard events
• Add UIBase: base class for all UI to manage visibility, blocked controls, custom window (specific design when controls are locked)...

Console

• Virtual extends from UIBase
• Use custom window from UIBase (remove console-level window design when controls are locked in favor of global behavior)
• Remove Multiline (not compatible with history: https://github.com/ocornut/imgui/blob/master/imgui_widgets.cpp#L4093)
• Remove the control lock toggle in favor of global integration at project level
• Improve design when controls unlocked (no scrollbar, no ghost spacing, padding fixes, ...)
• Cleanup code (useless condition, variable names, indentation, ...)