Notes Feature for PhotoInput and Photo components

[charliepnnl]

Allow the user to add notes associated with each photo in PhotoInput. The notes should be a TextInput that appears underneath the photo. If the notes text is non-empty, it should be shown under the corresponding photo in the Photo component.

This will require a scheme by which data is stored in the document that is associated with an attachment. Consider adding a top-level attachments_metadata_ field to the document. attachements_metadata_ is an object that maps attachment ids to corresponding metadata object in which we include a notes field. Functionality will need to be added to the Store to make this data available through Context and to allow this data to be upserted.