DDBNEXT-765: create the class for the saved search service
DDBNEXT-765: disable integration tests for newsletter.
DDBNEXT-765: add test skeleton
Merge branch 'develop' of https://github.com/Deutsche-Digitale-Bibliothek/ddb-next into develop
DDBNEXT-765: saving user's search.

   title and description are _not_ stored yet.
DDBNEXT-765: wip
DDBNEXT-765: implement find all saved searches by user ID
DDBNEXT-765: implement delete saved searches by their IDs.
Merge branch 'feature/DDBNEXT-765' of https://github.com/Deutsche-Digitale-Bibliothek/ddb-next into feature/DDBNEXT-765
DDBNEXT-765: change service url
Merge branch 'develop' of https://github.com/Deutsche-Digitale-Bibliothek/ddb-next into develop
Merge branch 'develop' of https://github.com/Deutsche-Digitale-Bibliothek/ddb-next into develop
Merge branch 'feature/DDBNEXT-765' into develop