refactor(output): cleaner initialization of output generators

[kschrab]

Description

• Previously, implementations of OutputGenerator had to override the initialize method and were required to call super.initialize, which is a anti-pattern to avoid.
• This MR marks initialize as a final method and defines an additional abstract configure method which all subclasses need to implement to read additional parameters from the output generator configuration.

Issue(s) related to this PR

• Resolves internal issue 875

Affected parts of the online documentation

Changes in the documentation required?

No

Definition of Done

Prerequisites

• You have read CONTRIBUTING.md carefully.
• You have signed the Contributor License Agreement.
• Your GitHub user id is linked with your Eclipse Account.

Required

• The title of this merge request follows the scheme type(scope): description (in the style of Conventional Commits)
• You have assigned a suitable label to this pull request (e.g., enhancement, or bugfix)
• origin/main has been merged into your Fork.
• Coding guidelines have been followed (see CONTRIBUTING.md).
• All checks on GitHub pass.
• All tests on Jenkins pass.

Requested (can be enforced by maintainers)

• New functionality is covered by unit tests or integration tests. Code coverage must not decrease.
• If a bug has been fixed, a new unit test has been written (beforehand) to prove misbehavior
• There are no new SpotBugs warnings.

Special notes to reviewer

[schwepmo]

LGTM, this is a way nicer solution!