Issues after DBEN merge

[stineb]

@lauramarques

Remaining issues after merge:

• [x] I corrected some erroneous annual cohorts output writing. But some remain. See compilation warnings. Please resolve them.
• [ ] Update documentation of biomee R functions with revised output variables

Please take note of the following changes I had to make on the master branch after your PR was merged:

• output_annual_cohorts_nsn written multiple times in SR biomee_f. I corrected it now.
• I changed timings and frequency of output writing output_annual_cohorts to how it was before
• I commented out "Reset vegetation to initial conditions" in SR biosphere_annual
• I removed validation plant C line in biomee_use vignette