[lldb/Plugin] Add breakpoint setting support to ScriptedProcesses.

[lldb/Plugin] Add breakpoint setting support to ScriptedProcesses.

This patch adds support for breakpoint setting to Scripted Processes.

For now, Scripted Processes only support setting software breakpoints.

When doing interactive scripted process debugging, it makes use of the
memory writing capability to write the trap opcodes in the memory of the
driving process. However the real process' target doesn't keep track of
the breakpoints that got added by the scripted process. This is a design
that we might need to change in the future, since we'll probably need to
do some book keeping to handle breakpoints that were set by different
scripted processes.

Differential Revision: https://reviews.llvm.org/D145296

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