Implemented folder support

[IceboxDev]

Fixes

• Fixed version: 1, didn't even compile with checks against v2 throwing error
• Fixed ioutil Deprecated: As of Go 1.16, the same functionality is now provided by package io or package os, and those implementations should be preferred in new code. See the specific function documentation for details.
• Fixed comment typo
• 93e08e6, 0b225ad fixed multiple uncaught errors

New

• Implemented folder support
• 93e08e6 all option lists can now be handled as single or multiple choice. The value of the corresponding env variable will be all choices separated with ;
• by request of @r0l1, c77cb1b now supports this path format:

options:
    test_dir: my_dir/*.yaml