add relational quantity value #1875

[stap-m]

Summary of the discussion

A relational quantity value is a quantity value that quantifies two or more quantities in relation to each other.

• > * Bezug von full load hours zu process über process atttribute performance
• > * market share value zu fraction value
• > * area per power value als relational quantity value für specific space requirement, will be done together with space requirement, see [meta] Restructure quantity values #1875 (comment)
• > * annual GDP growth
• > * discount rate
• > * exchange rate
• > * inflation rate
• > * all monetary prices, will be done in Restructuring quantities and quantity values: Monetary value, Price and Cost #1902
• > * purchasing power parity

Type of change (CHANGELOG.md)

Add

• relational quantity value

Update

• fraction value, full load hours, market share value, annual gdp growth, discount rate, exchange rate, inflation rate, PPP

Remove

• Removed a broken link #

Workflow checklist

Automation

Closes #1911

PR-Assignee

• 🐙 Follow the Pull Request Workflow
• 📝 Update the CHANGELOG.md
• 📙 Add #'s to term tracker item

Reviewer

• 🐙 Follow the Reviewer Guide
• 🐙 Provided feedback and show sufficient appreciation for the work done

[l-emele]

Looks fine