Execute e2e specs for review app inside gitlab-qa image directly

What does this MR do?

This MR slightly simplifies e2e test execution against review-app environment:

• Uses gitlab-qa image directly as runner environment and skips starting it via gitlab-qa gem
• Removes parallel-rspec-report. It seems to be unused and some of the code is outdated, so screenshots do not work in the report anymore. Allure report provides aggregate report with a better UI experience instead in place of default rspec html one.

Conformity

• [-] I have included changelog trailers, or none are needed. (Does this MR need a changelog?)
• I have added/updated documentation, or it's not needed. (Is documentation required?)
• [-] I have properly separated EE content from FOSS, or this MR is FOSS only. (Where should EE code go?)
• [-] I have added information for database reviewers in the MR description, or it's not needed. (Does this MR have database related changes?)
• I have self-reviewed this MR per code review guidelines.
• [-] This MR does not harm performance, or I have asked a reviewer to help assess the performance impact. (Merge request performance guidelines)
• I have followed the style guides.
• [-] This change is backwards compatible across updates, or this does not apply.