Merger: porting of authority framework functionalities

[FrancescoMolinaro]

References

• Fixes [DSpace-CRIS] Data model preparation work (Authority Framework enhancements, etc) DSpace#11748
• Requires backend PR: MERGER: porting authority framework DSpace#11718

##Description

Initial port of the DSpace-CRIS authority framework into core DSpace, enabling real-time entity lookup, confidence-based linking, and automatic graph maintenance through server-side consumers.

On the UI this PR introduces a new way to link authorithy controlled metadata to the related item, generating a link in search results or item page, this connection is handled in submission. (for configuration check the rest PR)

The information of the related item are previewed via a new pop-up component enabled on hover:

##Instructions for Reviewers

During submission, it provides real-time Solr-based lookup of authority records with confidence scores; server-side consumers then handle graph integrity by creating missing items, resolving placeholders, relinking text metadata, and enriching with virtual fields.

Once the item relation is enstablished (submitted) the metadata will be linking to the related item, with a preview of metadata visible on link hover.

The new configuration for the preview is available in default-app.config.ts, under the name:

metadataLinkViewPopoverData

It provides the opportunity to customize the preview metadata based on entity type.

In submission is possible also to configure specific icons for each source of authority, see config:

sourceIcons (under authority config)

List of changes in this PR:

Enhanced search results and item page with linkable related items (authority controlled)
Added new popover component for metadata preview on hover.
Implemented custom pipe for icon/info handling in onebox component.
Improved editing of authority via admin view, improved handling of search filters (filter by authorithy not value).

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