Tweak journal and departments autosuggest

[timdegroote]

• Change the results list height to show 5 results max
• Add a scrollbar for items which can't be shown initially
• Increase the result limit to 50

[timdegroote]

Assigning @ucamhal for review.

[timdegroote]

This implements the UI part for https://github.com/CUL-DigitalServices/avocet-ui/issues/335.

[bertpareyn]

Verified and merged