enable data-processing of 202507 campaign (MR !20)

issue

• another field campaign will be conducted in July 2025
• to quality-check GHG concentrations during the campaign, it is important we can run the data every evening --> implement 2025 campaign (NEW)
• minimum goal: run plots to visualise GHG concentrations (pre-processing part 1)
• optimum goal: prepare the whole script, so that GHG flux calculations work, too

solution

• where ever measCamp is mentioned, 202507 was added as "normal", new measurement campaign
• no major code changes needed

testing

• tested for real data from 202408 campaign (small data frame) for N2O, CO2, and CH4
• everything runs successfully, including visualisation of GHG concentrations and GHG flux calculations

Closes #32 (closed)