Follow-up from "Support specific deadline for each category of project."

The following discussions from !18 (merged) should be addressed:

• @ip914 started a discussion:

  Feels like you are mixing two concerns here: a validation concern and a data postprocessing concern

• @ip914 started a discussion:

  I would reorder the params to allow for default value for allow_edit:

  {% macro project_list(header, projects, allow_create, allow_edit={}) %}

  In this way you don't need to pass an empty dictionary as on line 45.