Add monitoring events to site selection and downscaling.

[dlebauer]

For MVP stick with the most simple justifiable encoding.

For example:

• irrigation (conventional, reduced, drip)
• fertilization (conventional mineral N, reduced mineral N, organic N)
• cropping history (already done as EOFs but could've been categorical but it complicated)
• tillage (categorical zero, reduced, conventional)

EOFs are OK, ideally interpretable, but only if it is simpler or more justified than categories like those above.