[E2E] Parametrize docker to set test suite

[Katka92]

What does this PR do?

Add TEST_SUITE variable to docker run command. Now user can set the command from package.json that specifies the suite that will be run.
Add example of TEST_SUITE usage to README.md.

Is related to #14027

[che-bot]

E2E tests of Eclipse Che Multiuser on OCP has failed:

• Build details
• Test report
• docker image: eclipseche/che-server:14507
  https://github.com/orgs/eclipse/teams/eclipse-che-qa please check this report.
  Use command "ci-test" to rerun the test.

[che-bot]

E2E Happy path tests of Eclipse Che Single User on K8S (minikube v1.1.1) has been successful:

• build details
• "che-server" docker image: maxura/che-server:14507

[Katka92]

ci-test

[che-bot]

E2E tests of Eclipse Che Multiuser on OCP has failed:

• Build details
• Test report
• docker image: eclipseche/che-server:14507
  https://github.com/orgs/eclipse/teams/eclipse-che-qa please check this report.
  Use command "ci-test" to rerun the test.

[Katka92]

ci-build

[dmytro-ndp]

Looks good.

[che-bot]

E2E Happy path tests of Eclipse Che Single User on K8S (minikube v1.1.1) has been successful:

• build details
• "che-server" docker image: maxura/che-server:14507

[che-bot]

E2E tests of Eclipse Che Multiuser on OCP has failed:

• Build details
• Test report
• docker image: eclipseche/che-server:14507
  https://github.com/orgs/eclipse/teams/eclipse-che-qa please check this report.
  Use command "ci-test" to rerun the test.