Support nested classes in CLI

[volivan239]

Description

Currently when generating tests with cli, it won't generate tests for methods located in nested classes even though engine and codegen have such possibilities.

Expected behavior

Launching UTBot from cli on the following class should produce tests for method f():

class Outer {
    public static class Inner {
          public int f() {
              return 0;
          }
    }
}

Context

Generating tests for methods from nested classes is already supported in plugin and contest estimator