Fixes #1350 - Update Bootstrap to 5.3.3
Update references to bootstrap.min.css and bootstrap.min.js as well as popperjs. Added integrity hashes and crossorigin attribute where possible.
Integrity hashes taken from: https://getbootstrap.com/docs/5.3/getting-started/download/
Signed-off-by: Thomas Darimont thomas.darimont@oidf.org