restructure amount

[sbello]

From the UPheno call on Jan, 26 2024 Request changes to PATO

• [x] Create a quantitative branch
• [x] Move amount under this
• [x] Make concentration a child of amount
• [x] Remove reciprocal relation to ‘has number of’
• [x] Make has number of a child of amount

See minutes https://docs.google.com/document/d/1WrQanAMuccS-oaoAIb9yWQAd4Rvy3R3mU01v9wHbriM/edit?usp=sharing

[sbello]

Would also be good to define qualitative

[rays22]

• quantitative Proposed textual definition: A quality relating to an amount or number that can be measured or counted.