CodeRunner: multi-language support

[Cam]

Design/Refactor CodeRunner module to support running compiled and interpreted languages.

Currently, to support compiled languages, the compile and run step have to be executed "together" (link). This issue is to create a PreRunHook interface that implements any steps required before running the code. An example of how this could be used is writing the sourcecode to file for Python or writing to file and compiling to binary for C++.

Requirements:

• "easy" to add another language (easy can be defined many ways, let's say adding support for Node shouldn't take more than a week?)
• supports compiled and interpreted code execution

Example interface:

type CodeRunner interface {
    PreRunHook(lang Language, filename string) (RunProps, error)
    Run(props RunProps) (RunResponse, error)
    PostRunHook(filepath string) (error)
}

Currently implementation is here.

Example execution structure:

func (r *CodeRunner) Run(req *RunnerProps) (*RunnerOutput, error) {
    // error handling ...

    // handles writing to filename.extension and compiling code if needed
    runProps, err = r.runner.PreRunHook(r.language, runDirectoryTmp)

    // error handling
    resp, err := Run(runProps)
    
    // cleanup
    // ...
    // return output
}

• CodeRunner function accepts variable language and code snippet

  • CodeRunner can internally handles compiling step if needed
  • CodeRunner may temporarily store user code in filesystem
  • CodeRunner deletes user code after running
  • Unit test for multi-language feature

• End to End test for basic code snippet

[Cam]

Closed by #82 though there is opportunity to add more languages and further improve the language support.

Will create a separate issue to track adding more languages.