Help with generating test cases in addition to static tests

[jabluko]

While creating problem packages I found myself with some static tests, and wanted to generate additional with ingen.

There are a couple of solutions:

1. hard-coding a list of static tests into ingen. (tedious)
2. move copy_package_required_files to before generate_input_tests, allowing ingen to parse config.yml during sinol-make export.
3. make sinol-make create a (temporary during ingen, persistent on export) file static-tests.in. This file should contains a list of static tests, each in a separate line, so ingen can read it as-is, without parsing.

This feature is especially important on training contests where tasks are often times adopted from older packages, which do not have an ingen.