[EIC Recommendations] Remove "requested changes" field

Current situation

The EiC is now requested to fill out 3 fields when making a recommendation:

• Remarks for authors
• Requested changes
• Remarks for the EC

I believe that the form would be improved if "requested changes" were removed:

• Conceptually, requested changes are also a remark for the authors.
• Some editorial decisions should not contain requested changes, specifically the decision to accept or reject the manuscript.

On a database level, the two columns can be just merged.