External source support

[KSAlpha]

Soma supports local file sources only. However, there are some situations users may want to use external file source.

• File is too big

  Git repositories may have a repository size limit. Also, putting a large file into repository directly may result in slow update and excessive disk usage.

• Cannot include the file directly due to legal issues

  Some license may prohibit problem makers to include the file directly into the repository.