Add study related to collections

[svituz]

This PR adds the possibility to link a clinical study to one or more collections. The clinical study is the context in which the collections of samples were generated.
This PR is needed to link BBMRI ERIC collections with ECRIN MDR clinical studies

The PR implements the following changes:

• Model:
  • adds the eu_bbmri_eric_studies entity with some attributes for the studies
  • adds to eu_bbmri_eric_collections entity the nillable attribute study that references a study
  • changes the attribute national_node of the eu_bbmri_eric_also_know_in entity to be nillable. Indeed, in case the also_known entity is used to store information for a study, the national node is null, since the concept is not related to a study
• UI
  • adds to the Collection page, in the info card on the right, a link to the details of the Study, if present
  • adds a Study page with the information of the Study. The page contains study attributes, the list of collections with the samples of the study, and an info card that just contains the link to the external catalog if present

A working demo can be found at http://rd-demo.directory.bbmri-eric.eu/ . An example of a collection is http://rd-demo.directory.bbmri-eric.eu/#/collection/bbmri-eric:ID:AT_MUG:collection:TheCoVVacBoostStudy-COVID-19boostervaccination From here it is possible to navigate to the Study page using the link in the info card on the right

Checklist

• [] Functionality works & meets specifications
• [] Code reviewed
• Code unit/integration/system tested
• User documentation updated
• Clean commits
• No warnings during install
• Added to release notes

[konradlang]

Is there a possibility to use the study to link generated data to collections, e.g. use this to link back generated data?