[lldb/bindings] Add Python ScriptedProcess base class to lldb module
In order to facilitate the writting of Scripted Processes, this patch
introduces a ScriptedProcess python base class in the lldb module.
The base class holds the python interface with all the - abstract -
methods that need to be implemented by the inherited class but also some
methods that can be overwritten.
This patch also provides an example of a Scripted Process with the
Differential Revision: https://reviews.llvm.org/D95712
Signed-off-by: Med Ismail Bennani <firstname.lastname@example.org>