SciX ID support for networks

[ehenneken]

This PR contains support for the SciX ID in the visualizations. Both the Paper Network and Author Network are generated by means of POST requests. These POST requests can either contain a query or a list of, before this PR, bibcodes. In the implementation of the networks within the context of the UI, only POST requests with a query in the payload are submitted. So, for the data gathering phase in the views.py module, the following changes were implemented

• Submission of query: the scix_id field was added to the list of fields for which to retrieve data in a Solr query
• Submission of identifiers: backwards compatibility was left in by keeping a bibcodes parameter and the option of specifying an identifiers field was added to support the submission of other identifiers, specifically SciX IDs

While programmatically not required, it felt "cleaner" to have a field called identifiers. It should be noted that no applications are known that make use of this endpoint. This endpoint will function with SciX IDs as soon as they are indexed in the identifier field in production. The author network, using the identifiers payload was successfully tested by submitting ASCL IDs, like

params['identifiers'] = ["ascl:2501.001","ascl:2501.002","ascl:2501.003","ascl:2501.004","ascl:2501.005","ascl:2501.006","ascl:2501.007","ascl:2501.008","ascl:2501.009","ascl:2501.010"]

The changes in the remainder of the networks consist of replacing the use of the word bibcode in comments and the replacement of the keyword bibcode by scix_id in data dictionaries. The actual calculation of the network and the clustering are done using integers.

Unit tests were updated appropriately, together with stab data (by adding scix_id fields to data structures).

No changes were required for the word-cloud endpoint. The Results Graph is not part of vis-services; it consists of a single BigQuery query from within the UI where it will have to be updated to use SciX IDs.

[kelockhart]

Looks good!