Write order key based on total order

[nanonyme]

We follow these four rules always in order

1. Elements that are not runtime dependencies come first
2. Elements whose names are alphabetically earlier come first
3. Elements which are junctioned come first
4. Elements whose junction is alphabetically earlier come first

[juergbi]

We're not merging this right now as it changes staging order and cache keys with all Python versions. #1993 solves the issue with Python 3.13 without changing cache keys for Python <= 3.12.

A new algorithm, such as the one in this PR, may follow as optional alternative in the future.

[nanonyme]

We're not merging this right now as it changes staging order and cache keys with all Python versions. #1993 solves the issue with Python 3.13 without changing cache keys for Python <= 3.12.

A new algorithm, such as the one in this PR, may follow as optional alternative in the future.

I agree, this solution does not seem acceptable. The more I've been reading, the nore it seems real solution needs to be topological sort. We actually want specific order from elements where dependencies are taken into account. It's not certain if Python 3.12 order is correct either. Python 3.11 changed sort function and after that all bets are off.