Integrated access to the pdb debugger and the Python profiler.

Now VS Code's generic debugger UI supports all data breakpoint access types defined in the Debug Adapter Protocol as context menu actions in the VARIABLES view: Break on Value Read: breakpoint will be hit every time a variable gets read. Break on Value Change: breakpoint will be hit every time a variable gets changed (this action was previously available). Break on Value Access: breakpoint will be hit every time a variable is read or changed.