some adjustments to diffCurvPhaseIn2Lin, add Laurin as author

[orichters]

Purpose of this PR

• ttot$((ttot.val ge cm_startyear) is t
• update docu: convergence year is 2050, not 2040
• fix warning in climate assessment because file does not yet exist
• relax fixOnRef precision to avoid 'errors' such as 0.0000139 % deviation
• add Laurin as new author + add some orcids

Type of change

• Refactoring
• Author update

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
• I adjusted the reporting in remind2 where it was needed
• I adjusted forbiddenColumnNames in readCheckScenarioConfig.R in case the PR leads to deprecated switches
• All automated model tests pass (FAIL 0 in the output of make test)
• The changelog CHANGELOG.md has been updated correctly