Support user-defined configurations and profiles in Spring integration test code generation

[sofurihafe]

Description

This PR adds support for user-defined configurations and profiles in Spring integration tests

Also, this PR has fixes for inner class Spring configurations.

Fixes #2292, #2338

How to test

Manual tests

Checking annotations in integration tests:

1. (optional) Open spring-boot-testing-main project.
2. Choose OrderService.getOrders() method for test generation with selected 100% fuzzer option, selected OrderServiceApplication configuration and any profile and selected integration test generation option.
3. Verify that class under test has two annotations: @activeprofiles(...) and @ContextConfiguration(...):

@ActiveProfiles(profiles = {"dev", "test"})
@ContextConfiguration(classes = {OrderServiceApplication.class})
@ExtendWith(SpringExtension.class)
@BootstrapWith(SpringBootTestContextBootstrapper.class)
@DirtiesContext(classMode = DirtiesContext.ClassMode.BEFORE_EACH_TEST_METHOD)
@Transactional
@AutoConfigureTestDatabase
public class OrderServiceTest {
    <...>
}

Checking inner class configuration:

1. (optional) Open TwoAnimals project.
2. Add inner class configuration, e.g.

class OuterClass {
    @Configuration
    static class InnerDolphinConfig {

        @Bean
        public Animal animal() {
            return new Dophin("Flipper");
        }
    }
}

4. Open test generation window and select inner class configuration, unit test generation, run generation.
5. See that the test is generated successfully with corresponding content derived from configuration.

[IlyaMuravjov]

Instead of enum I suggest to introduce sealed interface SpringConfig with two implementations and use SpringConfig type to denote Spring configs instead of simply using String. We can choose appropriate implementation of SpringConfig in functions responsible for finding xml and Java configs.

[sofurihafe]

Discussed in person, it was decided to leave as it is for now.

[IlyaMuravjov]

Mostly LGTM