Expand contributions functionality

[dbirman]

After discussion w/ Jerome we want to build:

Back-end

• GET endpoint that returns the Myst YAML or aind-data-schema JSON of a set of contributions, these can optionally linked to a DOI but by default would have a UUID assigned
• POST endpoint that pushes a new contribution as YAML or JSON and links these to a parent UUID for versioning
• Store in aind-scratch-data for now?

Front-end

• Use the query builder tool from metadata portal to let users filter for data assets, or paste a list of data assets, or point to a public collection?
• Or load from an existing UUID
• Once data assets are selected, build an initial YAML, immediately POST and store and create a UUID for these
• Now users can modify levels, add/remove authors, link to a DOI, modify data assets list, and then "Save" (POST)

URL encodes query OR uuid + modifications performed