Debugger: Another set of #13800 fixes.

AbstractTable/Table/TreeTable:
- Let BColumnListView take care of deleting columns. The previous
approach was resulting in the columns being leaked.

Debugger:
- Don't detach the UI reference, as TeamDebugger will acquire its own.

GraphicalUserInterface:
- Cleanup of file panel handler.

SourceView:
- Clean up marker manager.

*Roster:
- Clean up registered objects in destructors.

GlobalTypeLookup:
- Clean up hash tables.

NetworkTargetHostInterfaceInfo:
- Fix reference handling for settings.

libdebugger: Minor fixes to NetworkTargetHostInterface classes.

NetworkTargetHostInterface:
- Fix missing initializer. This would lead to a crash in the destructor.

NetworkTargetHostInterfaceInfo:
- Implement IsConfigured() to validate passed in settings.

libdebugger: Add initial version of network interface.

NetworkTargetHostInterface{Info}:
- Barebones classes for implementing a target host interface over TCP.