delete old realizations of module 45_carbonprice

[LaviniaBaumstark]

Purpose of this PR

clean up REMIND and delete old realizations of the module 45_carbonprice: NDC2constant, NPi2018, diffPhaseIn2Constant, diffPhaseIn2Lin, diffPhaseInLin2LinFlex, diffPriceSameCost

Type of change

• Refactoring

Checklist:

• My code follows the coding etiquette
• I performed a self-review of my own code
• I explained my changes within the PR, particularly in hard-to-understand areas
• I checked that the in-code documentation is up-to-date
• All automated model tests pass (FAIL 0 in the output of make test)

Further information (optional):

• Test runs are here:
• Comparison of results (what changes by this PR?):

[robertpietzcker]

could you add the list of deleted module realizations to the PR description? (with the 39 changed files this is not immediately clear :-)

[0UmfHxcvx5J7JoaOhFSs5mncnisTJJ6q]

• All automated model tests pass (FAIL 0 in the output of make test) (except the know issue with EU21 runs)

… and test_99-codeCheck.R, which gets skipped if any of the previous tests failed.

[orichters]

Fine from my side. I think it would merit updating the changelog, so it is easier to find out later what happened to the realizations. I side with Robert on summarizing that in the PR description as well, that can help finding such information faster.