Create INSTALL.debian12.sh

[rubentroncon]

• Replaced strings 'Ubuntu' -> 'Debian'
• Edited os_version_check() to check for Debian 12 instead of Ubuntu
• Set PHP package versions to 8.2 (because 8.4 was not available in default apt repositories)
• Fixed ssdeep install (apt install libfuzzy-dev and create symlink to /usr/local/lib, otherwise install fails)

Generic requirements in order to contribute to MISP:

• One Pull Request per fix/feature/change/...
• Keep the amount of commits per PR as small as possible: if for any reason, you need to fix your commit after the pull request, please squash the changes in one single commit (or tell us why not)
• Always make sure it is mergeable in the default branch (as of today 2020-05-05: branch 2.4)
• Please make sure Travis CI works on this request, or update the test cases if needed
• Any major changes adding a functionality should be disabled by default in the config

What does it do?

• It adds an install script for MISP on Debian to the repository
• It fixes an issue when installing ssdeep (Install fails because libfuzzy.so is not found)

Questions

• Does it require a DB change?
• Are you using it in production?
• Does it require a change in the API (PyMISP for example)?