Improve LUC CO2 emission dynamics

[flohump]

🐦 Description of this PR 🐦

This PR aims to improve LUC CO2 emission dynamics, especially until 2035.

• Limit for annual peatland rewetting (2% of degraded peatland per year) to avoid adhoc rewetting of degraded peatlands with introduction of CO2 price.
• Reactivated external scenario for damage from shifting agriculture (cfg$gms$s35_forest_damage <- 2). This improves LUC CO2 emissions in the near-term in LAM, and partly in SSA.
• Minimum CO2 price of 1 $ per ton CO2 on emissions from deforestation and other land conversion in all time steps to avoid sudden jumps in carbon stock changes. The impact is visible in RAW CO2 emissions without low pass filter in SSA, LAM and OAS. The minimum CO2 price does not change overall model dynamics. Especially, net forest change is similar with and w/o minimum CO2 price.

🔧 Checklist for PR creator 🔧

• Label pull request from the label list.

  • Low risk: Simple bugfixes (missing files, updated documentation, typos) or changes in start or output scripts
  • Medium risk: Uncritical changes in the model core (e.g. moderate modifications in non-default realizations)
  • High risk: Critical changes in model core or default settings (e.g. changing a model default or adjusting a core mechanic in the model)

• Self-review own code

  • No hard coded numbers and cluster/country/region names.
  • The new code doesn't contain declared but unused parameters or variables.
  • magpie4 R library has been updated accordingly and backwards compatible where necessary.
  • scenario_config.csv has been updated accordingly (important if default.cfg has been updated)

• Document changes

  • Add changes to CHANGELOG.md
  • Where relevant, put In-code documentation comments
  • Properly address updates in interfaces in the module documentations
  • run goxygen::goxygen() and verify the modified code is properly documented

• Perform test runs

  • Low risk:
    • Run a compilation check via Rscript start.R --> "compilation check"
  • Medium risk:
    • Run test runs via Rscript start.R --> "test runs"
    • Check logs for errors/warnings
  • High risk:
    • Run test runs via Rscript start.R --> "test runs"
    • Check logs for errors/warnings
    • Default run from the PR target branch for comparison
    • Provide relevant comparison plots (land-use, emissions, food prices, land-use intensity,...)

📉 Performance changes 📈

• Current develop branch default : 31 mins
• This PR's default : 31 mins

🚨 Checklist for reviewer 🚨

• PR is labeled correctly
• Code changes look reasonable
  • No hard coded numbers and cluster/country/region names.
  • No unnecessary increase in module interfaces
  • model behavior/performance is satisfactory.
• Changes are properly documented
  • CHANGELOG is updated correctly
  • Updates in interfaces have been properly addressed in the module documentations
  • In-code documentation looks appropriate
• content review done (at least 1)
• RSE review done (at least 1)