Support custom naming of `nvrtc` programs

[brandon-b-miller]

Currently the program name when compiling c++ code with Program always defaults to 'default_program'. This makes errors a little less descriptive than what is currently supported by numba-cuda. For instance when compiling an improperly formed c++ program with numba's NVRTC bindings, NVRTC will report

error.cu(4): error: identifier "SYNTAX" is undefined                                                                                                                                                                                     
    SYNTAX ERROR

But through the Program interface I'll always get

default_program(4): error: identifier "SYNTAX" is undefined                                                                                                                                                                              
    SYNTAX ERROR

To fix this, we could consume the name through the program constructor and keep track of it or extend ProgramOptions with an additional option, or something else.