Debugger: Split into core library and application.

- Add subfolder src/kits/debugger which contains the debugger's core
functionality and lower layers. Correspondingly add headers/private/debugger
for shared headers to be used by clients such as the Debugger application
and eventual remote_debug_server. Adjust various files to account for
differences as a result of the split and moves.
- Add libdebugger.so to minimal Jamfile.

Debugger: Add table cell editors for various value types.

TableCell{Bool,Enumeration}Editor:
- OptionPopUp-derived editors for their respective value types.

TableCellIntegerEditor:
- TextControl-derived editor for integer values that validates inputs
based on the target integer size and type.

Not actually used yet, but together with the previous changes, these lay
the groundwork for the remaining part of #9708.

Debugger: Add table cell editors for various value types.

TableCell{Bool,Enumeration}Editor:
- OptionPopUp-derived editors for their respective value types.

TableCellIntegerEditor:
- TextControl-derived editor for integer values that validates inputs
based on the target integer size and type.

Not actually used yet, but together with the previous changes, these lay
the groundwork for the remaining part of #9708.