change rcp settings for policy scenarios

[RahelMA]

Purpose of this PR

The purpose of this PR is to use the new rcp37 as prepared by @dklein-pik for the NDC and the NDC-LTS scenario to use the same MAgPIE input (that cover the afforestation NDC targets) in a REMIND stand alone as in a coupled system.

More details to the discussion can be found in this ISSUE.

This PR closes https://github.com/remindmodel/development_issues/issues/680

File comparison: /p/projects/rd3mod/github/repos/remindmodel/remind/develop/config/scenario_config.csv -> config/scenario_config.csv
Columns deleted: -
Columns added:   -
Renamed columns: -
Renamed rows:    -

Changes in the rows:
~ SSP2-NDC-LTS:
    cm_rcp_scen: rcp45 -> rcp37 (default: rcp45)
~ SSP2-NDC:
    cm_rcp_scen: rcp45 -> rcp37 (default: rcp45)

$allwarnings
NULL

Type of change

Indicate the items relevant for your PR by replacing ◻️ with ☑️.
Do not delete any lines. This makes it easier to understand which areas are affected by your changes and which are not.

Parts concerned

• ☑️ GAMS Code
• ☑️ R-scripts
• ◻️ Documentation (GAMS incode documentation, comments, tutorials)
• ◻️ Input data / CES parameters
• ◻️ Tests, CI/CD (continuous integration/deployment)
• ☑️ Configuration (switches in main.gms, default.cfg, and scenario_config*.csv files)
• ◻️ Other (please give a description)

Impact

• ◻️ Bug fix
• ◻️ Refactoring
• ◻️ New feature
• ◻️ Change of parameter values or input data (including CES parameters)
• ☑️ Minor change (default scenarios show only small differences)
• ◻️ Fundamental change of results of default scenarios

Checklist

Do not delete any line. Leave unfinished elements unchecked so others know how far along you are.
In the end all checkboxes must be ticked before you can merge.

• I executed the automated model tests (make test) after my final commit and all tests pass (FAIL 0)
• I adjusted the reporting in remind2 if and where it was needed
• I adjusted the madrat packages (mrremind and other packages involved) for input data generation if and where it was needed
• My code follows the coding etiquette
• I explained my changes within the PR, particularly in hard-to-understand areas
• I checked that the in-code documentation is up-to-date
• I adjusted forbiddenColumnNames in readCheckScenarioConfig.R in case the PR leads to deprecated switches
• I updated the CHANGELOG.md correctly (added, changed, fixed, removed, input data/calibration)

Further information (optional)

• Runs with these changes are here: /p/tmp/rahelma/NDCupdate/develop/output
• Comparison of results (what changes by this PR?):

[dklein-pik]

Thank you!