eUsage/agreements integration: select usage data provider

E-Resource statistics managed, harvested and stored in eUsage app will be linked to an agreement. In the longer run, there will be statistics previews in the agreements detail view.
Information on eUsage data (link to provider, different report previews etc) will form a separate accordeon in the agreement detail view.

The first step is to establish the connection between agreement and eUsage data.
By current design, the user can link one or several providers of eUsage data for resources from a certain agreement in the agreement.

create/delete link:
We provide a plugin (https://github.com/folio-org/ui-plugin-find-erm-usage-data-provider) to select usage data providers, that should be integrated into the edit/create agreement screen.

view link:
The linked usage data providers should be displayed in the (new) statistics accordeon within the agreement detail view. The providers should be realized as a link that takes the user to the provider detail view in the eUsage app.