[lldb/Plugins] Add Attach capabilities to ScriptedProcess

This patch adds process attach capabilities to the ScriptedProcess
plugin. This doesn't really expects a PID or process name, since the
process state is already script, however, this allows to create a
scripted process without requiring to have an executuble in the target.

In order to do so, this patch also turns the scripted process related
getters and setters from the `ProcessLaunchInfo` and
`ProcessAttachInfo` classes to a `ScriptedMetadata` instance and moves
it in the `ProcessInfo` class, so it can be accessed interchangeably.

This also adds the necessary SWIG wrappers to convert the internal
`Process{Attach,Launch}InfoSP` into a `SB{Attach,Launch}Info` to pass it
as argument the scripted process python implementation and convert it
back to the internal representation.

rdar://104577406

Differential Revision: https://reviews.llvm.org/D143104

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

lldb/source/Plugins/ScriptInterpreter/Python/ScriptedProcessPythonInterface.cpp

@@ -7,6 +7,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "lldb/Host/Config.h"
+#include "lldb/Target/Process.h"
 #include "lldb/Utility/Log.h"
 #include "lldb/Utility/Status.h"
 #include "lldb/lldb-enumerations.h"
@@ -67,6 +68,13 @@ StructuredData::DictionarySP ScriptedProcessPythonInterface::GetCapabilities() {
   return dict;
 }
 
+Status
+ScriptedProcessPythonInterface::Attach(const ProcessAttachInfo &attach_info) {
+  lldb::ProcessAttachInfoSP attach_info_sp =
+      std::make_shared<ProcessAttachInfo>(attach_info);
+  return GetStatusFromMethod("attach", attach_info_sp);
+}
+
 Status ScriptedProcessPythonInterface::Launch() {
   return GetStatusFromMethod("launch");
 }