Add logical OR to advanced search

[lukas-rotsching]

User story

1. As a user
2. I want to be able to connect filter settings with a logical OR
3. So that i can build even more powerful search queries

Acceptance criteria

• Currently we are only showing data that matches all filter settings at the same time. Add support for disjunctive logical connective.
• We also need a way to parenthesize atomic expressions and then put AND/OR between single atoms and between parenthesized groups. Boost weights then need to also be assignable to groups.
• The above may be hard to implement. Alternatively we could also only support terms in conjunctive/disjunctive normal form. If you choose to implement this, evaluate which normal form might be better suited here. Adapt the boost weights accordingly.
• Test this extensively and make sure the boost priority feature works as expected

Definition of done (DoD)

A feature is considered complete when

• All of its acceptance criteria have been met.
• It has been thoroughly tested.
• The code has been peer reviewed by the dedicated team.
• It can be seamlessly integrated into the main branch without causing any negative side effects.
• Its core functionality has been thoroughly documented.

DoD general criteria

• Feature has been fully implemented
• Feature has been merged into the mainline
• All acceptance criteria were met
• Product owner approved features
• All tests are passing
• Developers agreed to release