[lldb/Commands] Add command options for ScriptedProcess to ProcessLaunch

This patch adds a new command options to the CommandObjectProcessLaunch
for scripted processes.

Among the options, the user need to specify the class name managing the
scripted process. The user can also use a key-value dictionary holding
arbitrary data that will be passed to the managing class.

This patch also adds getters and setters to `SBLaunchInfo` for the
class name managing the scripted process and the dictionary.

rdar://65508855

Differential Review: https://reviews.llvm.org/D95710



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