[lldb/Plugins] Introduce Scripted Interface Factory

[lldb/Plugins] Introduce Scripted Interface Factory

This patch splits the previous `ScriptedProcessPythonInterface` into
multiple specific classes:

1. The `ScriptedInterface` abstract class that carries the interface
   instance object and its virtual pure abstract creation method.

2. The `ScriptedPythonInterface` that holds a generic `Dispatch` method that
   can be used by various interfaces to call python methods and also keeps a
   reference to the Python Script Interpreter instance.

3. The `ScriptedProcessInterface` that describes the base Scripted
   Process model with all the methods used in the underlying script.

All these components are used to refactor the `ScriptedProcessPythonInterface`
class, making it more modular.

This patch is also a requirement for the upcoming work on `ScriptedThread`.

Differential Revision: https://reviews.llvm.org/D107521

Signed-off-by: Med Ismail Bennani <medismail.bennani@gmail.com>