Support specifying command-line options

[ArielG-NV]

Problem:

• Currently, if we want to demonstrate slangc compile options (or test them), we need to use compiler-explorer (provides an interface)
• slang-playground does not support specifying command line options

Solution:

• Allow specifying command-line options (somehow) with slang-playground
  • This may require a more "manual" compile+output only mode which functions more like compiler explorer