Add project skeleton and basic structure

[camerondurham]

Adds skeleton code for project.

This PR so far includes:

• Engine module boilerplate
  • runs input commands and returns stdout/stderr
  • basic integration test
• rough implementation of multiple language support for CodeRunner
• API module GET /api/v1/languages endpoint hard-coded response
• API module POST /api/v1/run endpoint hard-coded response
• CLI had stubs for run and languages subcommands
• Basic unit test for coderunner
• Basic startup/shutdown test for server
• Github Workflow to verify tests pass

See #1 for details.

[camerondurham]

Should probably not have included go.sum since only the CLI is a binary.