[FEA]: Debugger pretty-printers: `cuda::std::optional`

[Jacobfaib]

Create a lldb and gdb pretty printer for cuda::std::optional.

The printer should live under libcudacxx/share/libcudacxx/<debugger>/optional.py for each debugger.

In addition, the pretty printers should be exhaustively tested, with tests living under libcudacxx/test/debugging/optional. See the existing tests in that directory for inspiration.

[aminehd]

Hi, I would like to work on this. I'll add the optional.py under libcudacxx/share/libcudacxx/gdb/ and .../lldb and will add exhaustive tests. I can work on #10099 as a follow up as well