Add multi-criteria decision analysis to the OEO

[madbkr]

Description of the issue

multi-criteria decision analysis (MCDA) is a term used in the definitions of the tasks module (see #1891). As decided in the dev meeting there should be a separate issue to discuss the definition.

Ideas of solution

I propose this definition:
multi-criteria decision analysis (MCDA) is a methodology to help with decision making by defining goals, priorities and weights.

Workflow checklist

• I discussed the issue with someone else than me before working on a solution
• [x ] I already read the latest version of the workflow for this repository
• [ x] The goal of this ontology is clear to me

I am aware that

• [ x] every entry in the ontology should have a definition
• [x ] classes should arise from concepts rather than from words