Support tags and file attachments for datastreams

[kjlippold]

Describe the feature you'd like and what it will do

1. Add support for tagging and supplemental file attachments to datastreams.
2. Change thing photos to thing file attachments. File attachments would work the same as photos, except with the addition of a mandatory type field and optional description field.
3. Update HydroServer's frontend to display files typed as photos in the photo gallery and all other files in a separate list or table with download buttons.
4. While photos could technically be attached to datastreams, its unlikely we need to display a gallery of datastream photos. Datastream file attachments should just all be displayed in a list or table where users can download them.
5. File attachments on things and datastreams would be stored as a flat list; we would not support folders or any other type of grouping beyond the thing or datastream they're attached to.
6. Datastream tags would be implemented identically to thing tags.

Why is this feature important?

Datastream tags would allow data managers to attach additional metadata to datastreams. This could include summary statistics (e.g., mean, minimum, maximum values), custom filtering or grouping fields, or other metadata relevant to their workflows.

We have also discussed supporting supplemental files for things and datastreams, such as rating curves or other non-photo documents. Currently, HydroServer assumes all uploaded files are photos, but does not enforce it. Updating this behavior would formalize support for multiple file types and ensure the frontend displays them appropriately based on type.

Tags and file attachments for things and datastreams would be very helpful for third-party apps using HydroServer by reducing the need to manage supplemental data outside HydroServer. Even for apps we're developing internally, this will reduce the number of updates we need to make to HydroServer's API to support those specific apps or use-cases that may not apply to everyone who wants to use HydroServer, and will help the core API remain more stable over time.

Is your feature request related to a problem? Please describe.

No response

Any additional comments?

Since we already have a tagging and photo framework for things in place, adding them for datastreams would be straightforward for the backend. There may need to be some discussion about frontend design for datastream tags and non-photo file attachments for both things and datastreams, but I imagine we already have components for most of this that can be reused.