This question seems to have the answer to your question: https://answers.atlassian.com/questions/74297.
Particularly, one answer gives this link: https://confluence.atlassian.com/display/CONFKB/How+to+Force+Links+to+Open+in+a+New+Window, which worked for me. However, where it says to go to 'Administration >> Custom HTML', it is actually 'cog icon >> General Configuration >> Custom HTML', under 'Look and Feel'. It will apply to every page in every space, but you can probably apply to a single space if you can find 'Custom HTML' in its configuration page.
...ollected feedback from users around the lack of shortcuts, and we’re here to address that: In next-gen projects, I miss the keyboard shortcuts badly. This is particularly true on the Board, but also i...
Connect with like-minded Atlassian users at free events near you!Find an event
Connect with like-minded Atlassian users at free events near you!
Unfortunately there are no Community Events near you at the moment.Host an event
You're one step closer to meeting fellow Atlassian users at your local event. Learn more about Community Events