Add IDs and/or more classes to collecting forms

[allanaaa]

Public collecting forms load their inputs with a few generic classes: "collecting-block-form" and then "field required" and "field-meta" and "inputs". Some IDs for unique inputs, as well as classes for groupings (label + input + the two surrounding divs) would be great for styling. We currently have more granularity on, e.g., the advanced search form, that this should mirror. (The advanced search page could have more IDs too, I think.)